JP5314563B2 - Inter-device communication system and communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inter-device communication system and a communication apparatus which can perform communication with slave devices more than the combination of the number of address setting input terminals while suppressing the number of input terminals necessary for address setting from the outside to the absolute minimum with respect to each of the plurality of slave devices connected to the same bus. <P>SOLUTION: The inter-device communication system is configured to output unique fixed serial data corresponding to each output terminal from the data output terminal (Dx) of one slave device in response to a slave address setting instruction simultaneously distributed from a master device 103 through a communication line 100 to each slave device 110, 120 and 130, and to supply serial data to the data input terminal SLA of the other slave device, and to decode the supplied serial data based on a preliminarily defined function relation, and to store the data in a prescribed data storage part as individual salve addresses, and to perform communication by using the stored individual slave addresses. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an inter-device communication system and a communication device using a serial communication bus, and more particularly to an inter-device communication system and a communication device that enable an addressing scheme for accessing various components.

There is a serial communication system as a system for connecting many electronic devices or circuit boards to a common bus.
In I2C-BUS (see Non-Patent Document 1), a serial communication system that has become widespread in recent years, at least one master device and a plurality of slave devices have two buses of SDA (Serial Data) and SCL (Serial Clock). Are connected in common to form a serial bus system.

In order for the master device to transmit data to each slave device, an identification ID called a slave address that identifies each slave device needs to be given. The slave address is assigned a unique slave address depending on the type of device.
In order to connect devices of the same type, a fixed part where the slave address cannot be changed and a programmable part by device pin setting are provided so that as many devices as possible can be connected to one I2C-BUS. Has been taken into account.

Since the number of bits that can be programmed is determined by the number of available pins, for example, when 3 bits can be changed by pin setting, it is possible to connect a maximum of eight similar devices to one bus.
Under the circumstances as described above, in recent years, serious problems such as duplication of slave addresses and insufficient number of programmable pins with respect to the total number of slave devices have been derived. In order to cope with such a problem, a technique using a bus switching circuit has already been proposed (see, for example, Patent Document 1).

  In the technique disclosed in Patent Document 1, the slave target address issued from the master device is not sent directly to the serial bus system, but the slave target address of the serial bus expansion circuit peculiar to this technical proposal is sent. The slave target address of the slave device is transmitted so that a plurality of devices having the same slave target address can be arranged in the same serial bus system.

In addition, a technique for eliminating the restriction on the number of addresses in principle by dynamically shifting the addresses of slave devices has already been proposed (see, for example, Patent Document 2).
However, since the bus switching circuit in the proposal of Patent Document 1 cannot connect devices with the same address on the same bus, the bus switching control must be performed after the bus division expansion circuit is provided for the overlapping portion. .

  On the other hand, in the case of the method of dynamically shifting the address in the proposal of Patent Document 2, it is necessary to secure at least three dedicated bits necessary for dynamically changing the address. For this reason, for multiple configurations where the number of slave devices connected to the same bus is 8 or less, a pull-up resistor is used in comparison with the conventional method using 3 bits by hard wire connection of input terminals. Such disadvantages as increasing the number of external circuits, such as adding, tend to be remarkable. In addition, it is necessary to continue the instruction transfer until the target device is reached, and in order to switch to another device, the instruction cycle must be re-executed from the reset every time. In principle, it is impossible to meet the demand to communicate faster by overcoming the order.

Japanese Patent Laid-Open No. 11-312139 Japanese Patent Laid-Open No. 9-244986

"UM10204_3" I2C-bus specification and user manual (cNXP B.V. 2007)

  The present invention has been made in view of the above situation, and the number of input terminals required for address setting from the outside is set for each of multiple components that are a plurality of devices connected to the same bus. It is an object of the present invention to provide an inter-device communication system and a communication device that enable communication with multiple components equal to or more than the combination of the number of address setting input terminals while minimizing the necessary number.

In order to solve the above problems, the present application proposes the following technologies.
(1) A master device and a plurality of slave devices are connected to a communication line having a serial data line and a clock line, and serial data transfer is performed between the master device and the corresponding slave device through the communication line using a predetermined communication protocol. In an inter-device communication system,
For each of the plurality of slave devices connected to the same communication line, the plurality of address setting input terminals more than the combination while minimizing the number of input terminals necessary for external address setting An inter-device communication system that enables communication with other slave devices,
Each of the plurality of slave devices is
In response to a slave address setting command by broadcast address notification delivered from the master device through the communication line, a predetermined number corresponding to each output terminal from one or more data output terminals other than the terminal connected to the communication line Default serial data output means for outputting default serial data which is unique serial data;
An individual slave corresponding to the slave address setting instruction by decoding serial data input from one or more data input terminals other than the terminal connected to the communication line based on a predefined function relationship Individual slave address setting means for writing to a predetermined data holding unit as an address,
In the period of the slave address setting instruction, when the predetermined serial data output means outputs the predetermined serial data, the individual slave address setting means performs the writing of the individual slave address in parallel and is set by the writing. Communication control means for performing communication by the individual slave address;
An inter-device communication system comprising:

In the inter-device communication system of (1), a master device and a plurality of slave devices are connected to a communication line having a serial data line and a clock line, and a predetermined amount is transmitted between the master device and the corresponding slave device through the communication line. Transfers serial data using a communication protocol.
Each of the plurality of slave devices in the above is a terminal other than a terminal connected to the communication line according to a slave address setting command by a broadcast address notification delivered from the master device through the communication line by the predetermined serial data output means The predetermined serial data, which is predetermined unique serial data corresponding to each output terminal, is output from one or more data output terminals.

Further, the individual slave address setting means decodes serial data input from one or more data input terminals other than the terminal connected to the communication line based on a predefined function relationship, and converts the decoded data into Write to a predetermined data holding unit as an individual slave address corresponding to the slave address setting command.
Further, when the communication control means causes the default serial data output means to output the default serial data during the period of the slave address setting command, the individual slave address setting means writes the individual slave address in parallel. Then, communication is performed using the individual slave address set by the writing.
Then, when the communication control means causes the default serial data output means to output the default serial data during the period of the slave address setting command, the individual slave address setting means writes the individual slave address in parallel. Then, communication is performed using the individual slave address set by the writing.

(2) In a predetermined serial data output terminal that is the data output terminal for outputting the predetermined serial data in one slave device of the plurality of slave devices, and in another slave device in the plurality of slave devices (1) The inter-device communication system according to (1), further comprising predetermined serial data transmission means connecting the predetermined serial data input terminal for inputting the predetermined serial data.

  In the inter-device communication system of (2), in particular, in the inter-device communication system of (1), the default is the data output terminal that outputs the default serial data in one slave device of the plurality of slave devices. A predetermined serial data transmission means for connecting a serial data output terminal and a predetermined serial data input terminal for inputting the predetermined serial data in another slave device among the plurality of slave devices; Corresponding slave devices are connected by means, and the individual slave address setting procedure can be executed by cooperation between the corresponding slave devices.

(3) A master device and a plurality of slave devices are connected to a communication line having a serial data line and a clock line, and serial data transfer is performed between the master device and the corresponding slave device through the communication line using a predetermined communication protocol. In a communication device suitable as the slave device in an inter-device communication system ,
For each of the plurality of slave devices connected to the same communication line, the plurality of address setting input terminals more than the combination while minimizing the number of input terminals necessary for external address setting A communication device that enables communication with a slave device of
In response to a slave address setting command by broadcast address notification delivered from the master device through the communication line, a predetermined number corresponding to each output terminal from one or more data output terminals other than the terminal connected to the communication line Default serial data output means for outputting default serial data which is unique serial data;
An individual slave corresponding to the slave address setting instruction by decoding serial data input from one or more data input terminals other than the terminal connected to the communication line based on a predefined function relationship Individual slave address setting means for writing to a predetermined data holding unit as an address,
In the period of the slave address setting instruction, when the predetermined serial data output means outputs the predetermined serial data, the individual slave address setting means performs the writing of the individual slave address in parallel and is set by the writing. Communication control means for performing communication by the individual slave address;
A communication apparatus comprising:

In the communication device of (3), a master device and a plurality of slave devices are connected to a communication line having a serial data line and a clock line, and a predetermined communication protocol is established between the master device and the corresponding slave device through the communication line. It is suitable as the slave device in the inter-device communication system that performs serial data transfer according to the above.
And, by the predetermined serial data output means, one or more data output terminals other than the terminal connected to the communication line according to the slave address setting command by the broadcast address notification delivered from the master device through the communication line To output predetermined serial data which is predetermined unique serial data corresponding to each output terminal.

Further, the individual slave address setting means decodes serial data input from one or more data input terminals other than the terminal connected to the communication line based on a predefined function relationship, and converts the decoded data into Write to a predetermined data holding unit as an individual slave address corresponding to the slave address setting command.
Further, when the communication control means causes the default serial data output means to output the default serial data during the period of the slave address setting command, the individual slave address setting means writes the individual slave address in parallel. Then, communication is performed using the individual slave address set by the writing.
Then, when the communication control means causes the default serial data output means to output the default serial data during the period of the slave address setting command, the individual slave address setting means writes the individual slave address in parallel. Then, communication is performed using the individual slave address set by the writing.

(4) An output switching means is provided for outputting the predetermined serial data during the slave address setting command period and outputting other information data during a period not corresponding to the slave address setting command period. (3) Communication apparatus.
In the communication device of (4), particularly in the communication device of (3), the output switching means causes the default serial data to be output during the slave address setting command period, and does not correspond to the slave address setting command period. Other information data is output during the period.

(5) The predetermined serial data output means is configured to output each of the predetermined serial data corresponding to each of the plurality of slave devices corresponding to each output terminal,
(3) or (3), further comprising predetermined serial data distribution means for distributing the predetermined serial data output from the predetermined serial data output means to the corresponding data input terminal in each of the plurality of slave devices. 4) The communication device according to any one of 4).

  In the communication device of the above (5), in particular, in the communication device of any one of (3) or (4), the predetermined serial data output means corresponds to each of the plurality of slave devices corresponding to each output terminal. The predetermined serial data corresponding to each is output. Then, the predetermined serial data output means distributes the predetermined serial data output from the predetermined serial data output means to the corresponding data input terminal in each of the plurality of slave devices.

(6) A master device and a plurality of slave devices are connected to a communication line having a serial data line and a clock line, and serial data transfer is performed between the master device and the corresponding slave device through the communication line using a predetermined communication protocol. In a communication device suitable as the slave device in an inter-device communication system ,
For each of the plurality of slave devices connected to the same communication line, the plurality of address setting input terminals more than the combination while minimizing the number of input terminals necessary for external address setting A communication device that enables communication with a slave device of
Determining slave address data representing the communication device with reference to data of a function relationship defined in advance for a predetermined logical value supplied to one or more data input terminals other than the terminal connected to the communication line; Individual slave address determination means for writing the determined slave address data as a specific slave address in a predetermined data holding unit;
Communication control means for performing communication by the individual slave address written in the data holding unit by the individual slave address determination means;
A communication apparatus comprising:

In the communication device of (6), a master device and a plurality of slave devices are connected to a communication line having a serial data line and a clock line, and a predetermined communication protocol is established between the master device and the corresponding slave device through the communication line. It is suitable as the slave device in the inter-device communication system that performs serial data transfer according to the above.
Then, the individual slave address determination means refers to the data related to the function defined in advance for the predetermined logical value supplied to one or more data input terminals other than the terminal connected to the communication line. Slave address data representing the device is determined, and the determined slave address data is written in a predetermined data holding unit as an individual slave address.
The communication control means performs communication using the individual slave address written in the data holding unit by the individual slave address determination means.

When sending a slave address setting command from the master device, the slave device can be generated and output even if it is added to the external terminal of the slave device to determine the slave address. The number of opportunities for setting slave addresses can be increased by the number of serial patterns.
Slave address management design is possible only with the terminal connection relationship between slave devices or a single slave device, eliminating the need for control of switches other than the inter-device communication system, and solving the address duplication problem It is possible to eliminate the need for an arbitration device or the like.

A function for determining a slave address, which can be replaced with an existing system by setting the same address as that in a case where it is always fixed (power connection, etc.) as in the existing system. Therefore, it is easy to move to expansion of multiple components.
Since the slave address setting command by the master device is determined and held once, there is no need to repeat exceptional settings other than normal communication in order to access between multiple components found in the prior art.

  The terminals that determine the slave address can be connected serially or in parallel between devices, and can also be self-connected, so they were used by devices with different numbers of inputs and outputs, such as family devices that are easily used on the same communication line. Even in this case, there are wide choices of wiring methods, and it is easy to place the device at an appropriate position. Therefore, it is possible to suppress performance degradation and expansion of the installation area due to restrictions on arrangement.

It is a systematic diagram showing the communication system between apparatuses as one embodiment of this invention. 3 is a flowchart showing an outline of a slave address setting scheme in the inter-device communication system of FIG. 1. It is a figure showing the form of the signal (data) exchanged between each part in the communication system between apparatuses of FIG. It is a figure showing the relationship between the serial ID supplied to the slave apparatus in the communication system between apparatuses of FIG. 1, and the function value corresponding to this. It is a block diagram showing the structural example of the slave apparatus applied to the communication system between apparatuses of FIG. 6 is a flowchart showing an operation of a single slave device in FIG. 5. It is a figure which illustrates the relationship between the signal supplied to the SLA terminal of the slave apparatus in the communication system between apparatuses of FIG. 1, and the slave address and function value corresponding to this. It is a systematic diagram showing other embodiment of the communication system between apparatuses of this invention. It is a systematic diagram showing other embodiment of the communication system between apparatuses of this invention. It is a systematic diagram showing other embodiment of the communication system between apparatuses of this invention, and a communication apparatus.

Hereinafter, the present invention will be clarified by describing embodiments of the present invention in detail with reference to the drawings.
FIG. 1 is a system diagram showing an inter-device communication system as one embodiment of the present invention.
The inter-device communication system of FIG. 1 employs a multiplex configuration in which a plurality of serial communication slave devices of the present invention are connected to the same serial communication bus.

The serial communication bus 100 can communicate with two communication lines of a serial clock (SCL) line 101 and a serial data (SDA) line 102, and the master device 103 controls the serial clock (SCL) line 101. The SDA line 102 transmits and receives data.
In this embodiment, unless otherwise specified, it is assumed that the system operates on the I2C communication protocol using the 7-bit address format in I2C (de facto standard) described in Non-Patent Document 1 described above, that is, normally The following description will be made assuming that the protocol part conforms to I2C.

The master device 103 performs I2C communication with each corresponding slave device through two lines of the SCL line 101 and the SDA line 102.
That is, the clock line 111 and the serial data line 112 of the first slave device 110 are connected to the corresponding SCL line 101 and SDA line 102, and the master device 103 is connected to the first slave device 110 through the clock line 111 and the data line 112. I2C bidirectional communication is performed.

The clock line 121 and serial data line 122 of the second slave device 120 are connected to the corresponding SCL line 101 and SDA line 102, and the master device 103 and the second slave device 120 are connected through the clock line 121 and data line 122. I2C bidirectional communication is performed.
Further, the clock line 131 and the serial data line 132 of the third slave device 130 are connected to the corresponding SCL line 101 and SDA line 102, and the master device 103 is connected to the third slave device 130 through the clock line 131 and the data line 132. I2C bidirectional communication is performed.

  The first slave device 110 is also connected to the first device 116 that is the object of direct control or information transmission by the D1B data output bus 114 and the data input bus 115. The first slave device 110 has a communication function, while the first device 116 has various extended functions such as measurement. As described above, the first slave device 110 and the first device 116 connected by the D1B data output bus 114 and the data input bus 115 constitute the first functional unit FU1.

In the system illustrated in FIG. 1, a second functional unit FU2 and a third functional unit FU3, which are functional units similar to the first functional unit FU1, are configured, and a total of three functional unit units are arranged.
That is, the second slave device 120 having a communication function, and the second device 126 having a variety of extended functions such as measurement and other direct control or information transmission targets are a D2B data output bus 124 and a data input bus. The second functional unit FU2 is configured by connecting at 125.

In addition, the third slave device 130 having a communication function and the third device 136 that is an object of direct control and has various extended functions such as measurement are connected by the D3B data output bus 134 and the data input bus 135. Thus, the third functional unit FU2 is configured.
In the I2C communication protocol, a 7-bit slave address followed by an eighth data direction bit is subsequently transmitted to a slave device that is a communication partner.

When the slave address is transmitted, each slave device that has received the slave address compares it with its own address, and determines that there is an instruction from the master device when the transmitted address matches its own address.
In general, a slave address has a fixed part that cannot be changed and a programmable part, and this programmable part when a plurality of devices of the same specification (slave devices in the illustrated example) are used in the communication system. Change to identify and connect. The number of bits of the programmable part is determined by the number of available terminals.

In the first slave device 110 in the inter-device communication system of FIG. 1, there is one terminal SLA that can be used for programming, that is, the programmable portion is 1 bit. Since this 1 bit can take logic 1 and logic 0, there are two types of programmable slave addresses.
As described above, since the first to third functional units FU1 to FU3 are provided in the embodiment of FIG. 1, three slave devices (first devices) are included in the communication bus 100 with the master device 103. Slave device 110, second slave device 120, and third slave device 130) are connected.

On the other hand, as described above, since there are two types of slave addresses, any two slave devices will not be identified and will attempt to communicate at the same time, so the communication of these will be separated without any intervention. Can not.
In such a situation, in the embodiment of FIG. 1, it is possible to set different slave addresses for the slave devices 110, 120, and 130 so that communication with the master device 103 can be separated separately. .

This method will be described next. To specify the three types of slave addresses separately, two programmable address bits are required. Now, assuming that the fixed address is “10101”, the slave address setting scheme for determining the lower 2 bits of “10101XX” is as follows.
FIG. 2 is a flowchart showing an outline of a slave address setting scheme in the inter-device communication system of FIG.
The communication devices (the master device 103, the first slave device 110, the second slave device 120, and the third slave device 130) are first in an initial state when the power is turned on (first slave device 110: S211, second device). 2 slave device 120: S221, third slave device 130: S231).

Next, the master device 103 sends a broadcast notification to each of the slave devices 110, 120, and 130. Accordingly, each slave device 110, 120, 130 receives this broadcast notification and starts its operation (first slave device 110: S212, second slave device 120: S222, third slave device 130: S232). ).
Here, the broadcast notification is a notification in which a master device does not sequentially issue requests to individual slave devices but designates a slave address for sending a request and transmits them all at once. -Corresponds to an address (General Call Address).
The first slave device 110 receives the slave address setting command H06 from the master device 103 (S213), and outputs a predefined serial code from the bus.

For convenience of explanation, in the embodiment of FIG. 1, each slave device 110, 120, 130 has a function of outputting an arbitrary value N as a serial value in synchronization with the SCL signal 301 like the bus signal DxB indicated by 311 in FIG. 3. It shall have.
In the broadcast notification command in FIG. 3, a logical value indicated by reference numeral 321 in the drawing is delivered on the SDA in synchronization with the SCL signal 301.
Further, the above-described serial value may be unique serial data that is arbitrarily defined in advance. However, for convenience of explanation, in this example, a bus code as shown by 334 in FIG. 3 is output, and each slave device 110, In 120 and 130, serial signals as indicated by 330, 331, 332, and 333 in the figure are generated and output from the respective terminals.

As shown in the flowchart of FIG. 2, apart from the mainstream processing flow in the first slave device 110, serial data is output to the third slave device 130 at the start timing of the operation of transferring serial signals between the slave devices ( S215). In FIG. 2, this is visually indicated by a broken line arrow SD1.
The serial data itself is continuous data from which the master clock is output for 8 clocks (S216).

  As described above, the first slave device 110 also has a function of receiving a serial signal from the SLA terminal simultaneously with the output of the serial signal from the D1 terminal (S214), and takes in synchronization with the master clock SCL. The serial signal (S216) received from the second slave device 120 based on the correspondence with the value represented by a predetermined function (function table, mathematical expression, etc.) (serial ID: dashed arrow line SD2) To obtain a programmable address bit value.

FIG. 4 is a diagram showing a correspondence relationship between a serial signal (serial ID) supplied to the slave device and a function value (function corresponding value) as a result of decoding this signal.
Although it is possible to input 8 bits in synchronization with the SCL, in this embodiment, the undefined bits are 2 bits, and these 2 bits are any 2 bits of the serial ID 8 bits. Good. Therefore, for this bit position, for example, MSB is the seventh bit, and the two bits of the second bit and the first bit are applied to this, and the slave address can be specified by these two bits.
Also, the function corresponding values in FIG. 4 do not need to have a table corresponding to all combinations of 7-bit slave addresses in I2C, it is sufficient if there are lower 2 bits corresponding to undefined 2 bits, Since these are unnecessary, these upper bits are uniformly written as “X” in FIG.

  In the above description, the correspondence relationship between the serial ID and the function value may correspond to the number of bits intended to be defined (the number of undefined bits) with a limited bit length, or all It may be associated with the address bit length. As in the former case, when the correspondence relationship with the function value is defined with a small number of bits of only undefined portions, each bit of the fixed portion where the program (modification) is not permitted does not ask the value. For this reason, the address determination method of the slave device applied in the embodiment of the present invention can also be applied to communication with a device (device) having an address with a different fixed part.

If the I2C 7-bit slave address is used as it is as a serial ID code, the correspondence is one-to-one. For this reason, a memory circuit capable of directly writing and holding a serial ID code is provided, so that it is not necessary to define a correspondence relationship with a function value as described above, and therefore a correspondence table or expression is omitted. can do.
The serial ID output of the first slave device 110 is supplied to the third slave device 130 through one of the output buses D1B [3: 0]. The serial signal SD1 (broken arrow line) that has started to be output from the above-described step S215 in the first slave device 110 is the SLA according to the processing flow as described above for the first slave device 110 in the third slave device 130. It is taken in from the terminal as a serial ID (S234) and used to determine the readable portion (programmable address bit value) of the slave device address in the third slave device 130.

  Accordingly, at least one of the four signals D1B [3: 0] output from the output bus D1B is paired with a portion other than the fixed address for which the third slave device 130 determines the slave device address in step S237. If not, the slave device address cannot be determined by SD1 which is the serial ID code supplied for the process of step S234 by the process of step S215.

For this reason, correspondence functions (tables, formulas, etc.) that are paired between devices that are supposed to be used on at least the same communication line by the above-described correspondence functions (tables, formulas, etc.). It is necessary to determine the relationship in advance.
As described above, the first slave device 110 outputs the serial ID in accordance with the broadcast notification command, while receiving the serial ID input from the SLA terminal. In the inter-device communication system in FIG. The slave device 120 and the third slave device 130 are configured such that different serial IDs are input in advance from their respective SLA terminals.

In the inter-device communication system of FIG. 1, the serial ID output D1B [1] from the D1 terminal of the first slave device 110 is supplied to the SLA terminal of the third slave device 130 through the wiring 133.
Further, the serial ID output D1B [2] from the D2 terminal of the second slave device 120 is supplied through the wiring 113 as an input to the SLA terminal of the first slave device 110.
On the other hand, the SLA terminal of the second slave device 120 is maintained in a logic 0 state by being supplied with a ground (GND) level signal through the wiring 123.

In the example of the flowchart of FIG. 2, the ground (GND) level signal supplied to the second slave device 120 is represented as SD0, and the serial ID signal indicated by 330 in FIG. 2 from the start of serial ID input (S224). It is assumed that the same logic “00000000” as the pattern is supplied.
Each slave device 110, 120, 130 receives the broadcast notification command transferred from the master device 103 and returns an ACK (acknowledge), and decodes the serial ID based on the correspondence shown in FIG. This result is set as programmable 2-bit address data. As a result, each of the slave devices 110, 120, and 130 holds the determined address of the own device.

In the inter-device communication system of FIG. 1, since the slave devices are connected as described above, the first slave device 110 receives “10101100” as the serial signal D [2] 332 in FIG.
On the other hand, the third slave device receives “10101010” as the serial signal D [1] 331 in FIG.
Further, as described above, the SLA terminal of the second slave device 120 is always grounded through the wiring 123 and is maintained in the logic 0 state, and the serial signal D [0] of 330 in FIG. Is received.

In the first slave device 110, the second slave device 120, and the third slave device 130, from the signals received as described above, the first slave device 110 is “10” based on the correspondence relationship in FIG. The three slave devices 130 set “01” and the second slave device 120 “00” as programmable address bits (FIG. 2: S217, S227, S237).
Next, the master device 103 releases the serial communication bus 100 (SCL line 101 and SDA line 102) (FIG. 2: S218, S228, S238). In these steps, the stop condition (STOP) is issued in I2C.

At the time of reaching steps S218, S228, and S238, the first slave device 110, the second slave device 120, and the third slave device 130 determine “XX” of the last two bits in the slave addresses. Yes.
That is, the slave address is “1010110” in the first slave device 110, “1010100” in the second slave device 120, and “1010101” in the third slave device 130.

The four types of serial IDs that are decoded and output based on the correspondence in FIG. 4 are related so that they can be paired with all of the addresses that can be read as slave addresses. All four possible addresses can be specified.
For this reason, the wiring 133 in the embodiment of FIG. 1 is connected to D1B [1], but “1010111” is selected as the slave address of the third slave device 130 so as not to overlap on the communication line. If desired, it may be connected to D1B [3].

After issuing the I2C stop condition in steps S218, S228, and S238, any other master device connected to the same communication line enters an idle state in which normal communication can be started (FIG. 2: S219, S229, and S239).
In the idle state of steps S219, S229, and S239, data is not sent to the first slave device 110, the second slave device 120, and the third slave device 130 without performing special control using the slave address as described above. Can be sent and received.

That is, after the master device 103 issues a broadcast notification and transitions to the above-described idle state (after issuing a stop condition), the master device 103 enters a general idle state related to the I2C bus. Since the addresses of the slave devices are determined in the above-described steps S217, S227, and S237, no special form of communication for address determination is required thereafter.
In other words, when performing communication, if the special procedure as described above is performed only once at the beginning, it can function as a normal inter-device communication system.

FIG. 5 is a block diagram showing a configuration example of a slave device applied to the inter-device communication system of FIG.
The slave device 500 in FIG. 5 corresponds to the first slave device 110, the second slave device 120, and the third slave device 130 in FIG. 1 and represents them representatively. In FIG. The reference numeral 500 is newly added.
The slave device 500 has an SDA terminal 501 and an SCL terminal 502 as well as an ordinary slave device of this type, and further includes an SLA terminal 503 that is a programmable addressing terminal.

Note that a plurality of programmable addressing terminals may be provided. In this case as well, the invention idea is not different, and the configuration having a single programmable addressing terminal is substantially obvious. For this reason, an example with a single programmable addressing terminal is described here.
The terminal portion 504 including the terminals H1, H2, and H3 in FIG. 5 corresponds to the data input bus 115 (125, 135) from the first device 116 (second device 126, third device 136) in FIG. ing.

The terminal unit 504 constitutes an input unit for data to be processed by the slave device 500 in the normal data processing circuit 511.
Further, the slave device 500 includes a data output bus 505 for outputting data as a result of performing the signal processing that is the original purpose.
The data output bus 505 in FIG. 5 corresponds to the data output bus 114 (124, 134) in FIG. 1, which is one or more data other than the terminals connected to the communication line 100 in the embodiment of the present invention. Output terminal.

With respect to the data output from the data output bus 505, the multiplexer 532 switches between the normal signal and the serial signal for address determination as described above so that the data can be output. Needless to say, such a multiplexer is not required in the case where the normal signal output terminal and the serial signal output terminal are provided separately.
The serial communication unit 510 merely exchanges data with the normal data processing circuit 511 in the case of this type of device.

However, in the embodiment of FIG. 5, when General Call, which is a broadcast notification, is received, the General Call Active unit 530 sets a flag signal and maintains this flag. Then, in accordance with this flag, the serial data generation circuit 531 generates n + 1 kinds of unique serial data of output D [n] (n is a natural number of 0 or more), and switches the multiplexer 532 to serial data output.
By the serial data generation circuit 531, the multiplexer 532, the data output bus 505, and the like, the predetermined unique serial data corresponding to each output terminal (each signal line 505) in the embodiment of the present invention. A predetermined serial data output means that is a predetermined serial data output means for outputting serial data is configured.

  The serial data receiving circuit 521 receives serial data from the SLA terminal 503, which is one or more data input terminals other than the terminal connected to the communication line 100, and decodes the received serial data in the Address Table block 520. To determine the address of the programmable part. That is, one or more serial data output as a serial ID by a device corresponding to the embodiment of the present invention used on the same communication line and an address that can be set by a slave address setting command are paired. A functional relationship (correspondence relationship) is set in the serial communication unit 510, and an address of a programmable portion is determined according to this functional relationship, and a slave address (address as a slave device) is set and held.

That is, the address table block 520, the serial data receiving circuit 521, the serial communication unit 510, and the like constitute the individual slave address setting means in the embodiment of the present invention.
Further, the communication control means in the embodiment of the present invention is configured to include a serial communication unit 510, an SCL terminal 502, a terminal unit 504, an SDA terminal 501, and the like. The communication control means causes the individual slave address setting means to write the individual slave address in parallel when the default serial data output means outputs the default serial data during the period of the slave address setting command. Communication is performed using the individual slave address set by.

  If attention is paid to the configuration of the inter-device communication system (FIG. 1), the terminal unit connected to the data output bus 505 on the output side of the multiplexer 532 is set to the predetermined serial data for setting the individual slave address. Forms the output terminal. Then, a predetermined serial data output terminal in one slave device (for example, the first slave device 110) configuring the inter-device communication system and a predetermined serial data in another slave device (for example, the third slave device 130) are input. A wiring 133 is provided as a predetermined serial data transmission means for connecting a predetermined serial data input terminal (SLA) which is a terminal, and the individual slave address setting procedure is executed by cooperation between a plurality of corresponding slave devices. obtain.

FIG. 6 is a flowchart showing the operation of the slave device 500 in FIG. 5 alone.
At the beginning of the operation, it is initialized by Power On Reset or the like (S600). In step S600, communication is not yet performed between the master device and the slave device.
In this state, the slave address of each slave device may not be set or a fixed address may be set by Power On Reset etc., but at any point before execution of the slave address setting command, Also good.

In this state, it is assumed that a slave address setting command is issued as a broadcast notification (General Call) through the communication line from the master device (S601).
In the slave device 500 compliant with I2C (FIG. 5), the serial communication unit 510 (FIG. 5) starts receiving a serial signal as a slave address setting command from the SDA terminal 501 and the SCL terminal 502. Then, upon receipt of the above-described H00 code which is the first byte of the general call address, the slave address writing preparation is started (S602).

  Next, 8 bits of serial data of the second byte are transferred (S603). When the transfer in step S603 is completed (S604), the only fixed address determined on the hardware that can be written as the slave address (the number of writable bits constituting the address is all 7-bit length) In some cases, some of them may be set and held (S605).

On the other hand, in the embodiment of the present invention, unlike the conventional device of this type, a process of outputting a serial signal is executed in response to the start of a slave address setting command (sending broadcast notification) from the master device. (S620).
That is, when receiving a general call as a broadcast notification, the general call active unit 530 (FIG. 5) sets a flag signal and maintains this flag, while switching the output of the multiplexer 532 (FIG. 5) by this flag (S621). ).

Then, the output operation of the serial ID generated by the serial data generation circuit 531 (FIG. 5) is started together with the start of the second byte of the general call address (S622).
In the serial ID output operation started in step S622, a unique [n] -bit serial ID is sent from the output D [n: 0] together with the 8-bit transfer that is the second byte of the general call address. This is performed in synchronization with the serial clock supplied to the terminal 502 (FIG. 5) (S623).

When the general call is completed, the flag of the general call active unit 530 (FIG. 5) is canceled, the multiplexer 532 (FIG. 5) is switched (S624), and the normal output operation is shifted (returned) (S625).
That is, the multiplexer 532 outputs the predetermined serial data during the slave address setting command period, and outputs other information data during a period not corresponding to the slave address setting instruction period. It functions as a certain output switching means.

  On the other hand, in the embodiment of the present invention, unlike the conventional apparatus of this type, serial signal input is received separately (S610). That is, in response to the slave address setting command from the master device, in parallel with the processing steps after step S620 described above, H00, which is the first byte of the general call address, is received and serialized from the SLA terminal 503 (FIG. 5) Preparation for receiving the ID input is started (S611).

Then, with the start of the second byte of the general call address, the serial ID supplied to the SLA terminal 503 is received in synchronization with the serial clock supplied to the SCL terminal 502 (FIG. 5) (S612).
In the serial ID reception operation started in step S612, m bits supplied to the SLA terminal 503 (FIG. 5) in synchronization with the 8th bit of the second byte (in this example, m is an arbitrary integer from 1 to 8) ) Is received (S613). Here, the serial ID received in step S613 is different from the serial ID output in step S623 described above (when viewed from this slave device, the data supplied from the outside and the output from the own device). Of the data to be processed).

  The receiving operation of the serial ID in step S613 is continued, and when the last bit of the general call address is received, the input serial ID is decoded by a predetermined function or table possessed by the slave device to correspond to the input serial ID. A slave address (the number of writable bits constituting the address may be all or a part of the 7-bit length) is set and held (S605).

The address set by the above steps is determined as the set slave address of the slave device, and thereafter, normal device-to-device communication is performed using this set slave address (S606).
In the embodiment of FIG. 1, the “n” bits described above are 8 bits. With 8 bits, 256 types of serial patterns can be generated, and as many addresses as the number of functions can be defined. Therefore, it is possible to assign all the I2C 7-bit slave addresses with one SLA.

In FIG. 1, the serial ID synchronized with the SCL (serial clock) is assumed to be 8 bits. However, the serial ID data is generated in synchronization with a clock having a high rate such as a system clock used internally by the slave device. If reception is performed, it is easy to further increase the number of serial bits, and it is possible to allocate more addresses.
The operation step S601 for issuing the broadcast notification described above, which is the next step after the initialization state (S600) such as so-called power-on reset, is not a multiplex configuration in which a plurality of slave devices are connected to the serial communication bus. As described above, a method of using SLA only with logic 0 or logic 1 is also conceivable.

When this method is adopted, the slave address is determined according to the SLA logic in accordance with the SLA logic in the same manner as the normal programmable address setting method, unless a broadcast notification command from the master device is generated after initialization. A correspondence relationship with the function value may be assigned so that there is no contradiction.
That is, before the broadcast notification command is generated, when the SLA is 0 and the slave address LSB is 0, it is assumed that the SLA is always 0, and “XXXXXX0” is associated with “00000000”. .

Similarly, when the SLA is 1 and the LSB of the slave address is 1, the SLA is always 1, and “XXXXXXX1” is associated with “11111111”.
As a result, when the SLA and the slave address LSB are used in the correspondence relationship as described above, the address becomes the same as that when the setting is made without performing the address setting by the broadcast notification instruction. Therefore, the present invention can be applied without contradiction even in a system that may not use the broadcast notification command.

Furthermore, although it is not general, not only the SLA fixed logics 1 and 0 but also the change state of the SLA from the initialization state is detected and the combination of those states is added, for example, from the initialization state It is also conceivable to perform state detection when the falling logic changes from 1 to 0 by a flip-flop or the like and state detection when the rising logic changes from 0 to 1.
And even in the case of a system in which the two change states as described above are added to the two fixed states and these states are summed to form a quaternary address, the SLA is not fixed before the broadcast notification command is issued. Corresponding to the case of changing between logic 1 and logic 0, if the logic after change is assigned to the LSB as “N”, the relationship shown in the correspondence table of FIG. 7 is established.

That is, the correspondence between the signal supplied to the SLA terminal before communication and the slave address is as shown in FIG. 7A, and the signal supplied to the SLA terminal before communication and the corresponding function value. The relationship is as shown in FIG.
Therefore, the above-described method of detecting the change state of the SLA from the initialization state can also be applied without contradiction, and the application range is expanded.
As described above, according to the present invention, even in a communication system with a small number of programmable slave address terminals, a serial ID is output from a plurality of arbitrary output pins of the slave device itself in response to a slave address setting command. By having the function of decoding the input from the slave address setting serial signal input terminal and associating it with the address, the slave address value can be selected by the number of serial ID outputs.

As a result, even if there is only one external terminal for determining the slave address, it is possible to increase the number of slave addresses, and the connection of terminals between slave devices or between a single slave device By appropriately selecting the relationship, the management design of the slave address becomes possible.
Further, it is not necessary to control other switches or the like, and an arbitration device other than the communication line can be made unnecessary.

Further, by setting the correspondence relationship for the function for determining the slave address in the same manner as in the existing system, it becomes easy to expand the multiple components while using it in a manner such as replacement for the existing system.
Furthermore, the setting of the correspondence relationship in the above is the same as the normal communication after being performed once, and therefore, it is not necessary to repeat the exceptional setting.

In the embodiment described with reference to FIG. 1, the connection of the serial ID signal takes the form of a so-called daisy chain in which a plurality of devices having multiple configurations are connected like a chain.
Here, in the technical idea of the present invention, the serial ID signal is generated and decoded at the same time, so by selecting its own serial ID output and supplying it to its own serial ID input, for example, FIG. A configuration as shown in FIG.

FIG. 8 is a system diagram showing another embodiment of the inter-device communication system of the present invention.
The inter-device communication system of FIG. 8 is configured not to cause duplication of slave addresses without having wiring between slave devices.
That is, as shown in the figure, each slave device selects a predetermined output from its own serial ID signal and supplies the selected output to its own serial ID input, that is, the SLA terminal. For the third slave device 130, the SLA terminal is grounded.

As in the system illustrated in FIG. 1, the first slave device 110 and the first device 116 constitute a functional unit FU1, the second slave device 120 and the second device 126 constitute a functional unit FU2, The three slave devices 130 and the third device 136 constitute a functional unit FU3.
By adopting such a configuration, it is possible to construct an inter-device communication system that does not cause duplication of slave addresses even in a situation where wiring between slave devices is difficult.

FIG. 9 is a system diagram showing still another embodiment of the inter-device communication system of the present invention.
In the inter-device communication system of FIG. 9, multiple configurations are made when multiple components connected to the same communication bus 100 are not the same specification devices but different devices.
In FIG. 9, the first slave device 110, the fourth slave device 140, and the fifth slave device 150 are devices having different specifications. In this case, the first slave device 110 and the first device 116 constitute a functional unit FU1, the fourth slave device 140 and the fourth device 146 constitute a functional unit FU4, and the fifth slave device 150 and the first device FU1. 3 unit 156 constitutes a functional unit FU5.

Even if multiple components are configured by different devices as in FIG. 9, if the devices connected on the same communication line have the function of the slave device of the present invention described above, parallel as shown in FIG. Even when the connection mode is adopted, duplication of slave addresses can be prevented.
That is, a slave device having a large number of serial ID output terminals even when there are no or few terminals usable as a serial ID output by wiring to supply serial ID signals in parallel between the slave devices. By connecting to different serial ID output terminals output from the slave, duplication of slave addresses can be prevented.

  That is, in the embodiment shown in FIG. 9, the predetermined serial data output means (output bus 114) receives the above-mentioned predetermined serial data corresponding to each of the plurality of slave devices 146 and 156 corresponding to each output terminal. A predetermined serial data distributing means (D2, D2) configured to distribute the predetermined serial data output from the predetermined serial data output means (114) to the corresponding data input terminals (SLA) in each of the plurality of slave devices 146, 156; D5 and D7 are distributed to each SLA).

FIG. 10 is a system diagram showing still another embodiment of the inter-device communication system and communication device of the present invention.
The inter-device communication system of FIG. 10 is also configured not to cause duplication of slave addresses without having wiring between slave devices.
The first slave device 110 and the first device 116 constitute a functional unit FU1, the second slave device 120 and the second device 126 constitute a functional unit FU2, and the third slave device 130 and the third device 136. The functional unit FU3 is configured by the same as the system illustrated in FIG.

In the embodiment of FIG. 10, the terminal SLA for determining the programmable slave address is fixed to logic 0 (ground) in the first slave device 110 and fixed to logic 1 (positive power supply voltage) in the second slave device 120. By using it, the slave address is not duplicated.
Further, since the slave address is determined based on the serial ID input from the SLA terminal, the serial ID can be generated without using a slave device as in the present invention.

In the embodiment of FIG. 10, since the information data SDA of the communication bus 100 becomes the serial signal of H06 in FIG. 3 (the second half of FIG. 3: 310), the correspondence between the serial ID and the function value in FIG. If defined in a manner corresponding to this H06, it can be used as a serial ID.
Even in the case of adopting a configuration in which the SLA terminal is not connected to the output of the slave device as in the embodiment of FIG. 10, it can be applied as a communication device on a conventional inter-device communication system.

100 ……………………………… Serial communication bus 101 …………………………… Serial clock (SCL) line 102 ……………………… Serial data (SDA) line 103 ………………………… Master device 110 ………………………… First slave devices 111, 121, 131 ...... Clock lines 112, 122 , 132... Data lines 113, 123, 133 ...... Wiring 114, 124, 134 ...... Data output bus 115, 125, 135 ...... Data input bus 116 ……………… First device 120 ……………………………… Second slave device 126 ……………………………… Second device 130 …………………… ………… Third slave device 136 ……………………………… Third Device 500 ……………………………… Slave device 501 ……………………………… SDA terminal 502 ……………………………… SCL terminal 503 ……… ……………………… SLA terminal 504 ……………………………… Terminal (data input bus)
505 ……………………………… Data output bus 510 ……………………………… Serial communication unit 511 ……………………………… Normal data processing circuit 520 ……………………………… Address Table block 521 ……………………………… Serial data receiving circuit 530 ……………………………… General Call Active section 531 ……………………………… Serial Data Generation Circuit 532 …………………………… Multiplexer

Claims (6)

Communication between devices in which a master device and a plurality of slave devices are connected to a communication line having a serial data line and a clock line, and serial data transfer is performed between the master device and the corresponding slave device through the communication line according to a predetermined communication protocol In the system,
For each of the plurality of slave devices connected to the same communication line, the plurality of address setting input terminals more than the combination while minimizing the number of input terminals necessary for external address setting An inter-device communication system that enables communication with other slave devices,
Each of the plurality of slave devices is
In response to a slave address setting command by broadcast address notification delivered from the master device through the communication line, a predetermined number corresponding to each output terminal from one or more data output terminals other than the terminal connected to the communication line Default serial data output means for outputting default serial data which is unique serial data;
An individual slave corresponding to the slave address setting instruction by decoding serial data input from one or more data input terminals other than the terminal connected to the communication line based on a predefined function relationship Individual slave address setting means for writing to a predetermined data holding unit as an address,
In the period of the slave address setting instruction, when the predetermined serial data output means outputs the predetermined serial data, the individual slave address setting means performs the writing of the individual slave address in parallel and is set by the writing. Communication control means for performing communication by the individual slave address;
An inter-device communication system comprising:   The predetermined serial data output terminal which is the data output terminal for outputting the predetermined serial data in one slave device of the plurality of slave devices, and the default serial in another slave device of the plurality of slave devices 2. The inter-device communication system according to claim 1, further comprising predetermined serial data transmission means for connecting to a predetermined serial data input terminal for inputting data. Communication between devices in which a master device and a plurality of slave devices are connected to a communication line having a serial data line and a clock line, and serial data transfer is performed between the master device and the corresponding slave device through the communication line according to a predetermined communication protocol In a communication device suitable as the slave device in a system ,
For each of the plurality of slave devices connected to the same communication line, the plurality of address setting input terminals more than the combination while minimizing the number of input terminals necessary for external address setting A communication device that enables communication with a slave device of
In response to a slave address setting command by broadcast address notification delivered from the master device through the communication line, a predetermined number corresponding to each output terminal from one or more data output terminals other than the terminal connected to the communication line Default serial data output means for outputting default serial data that is unique serial data,
An individual slave corresponding to the slave address setting instruction by decoding serial data input from one or more data input terminals other than the terminal connected to the communication line based on a predefined function relationship Individual slave address setting means for writing to a predetermined data holding unit as an address,
In the period of the slave address setting instruction, when the predetermined serial data output means outputs the predetermined serial data, the individual slave address setting means performs the writing of the individual slave address in parallel, and is set by the writing. Communication control means for performing communication by the individual slave address;
A communication apparatus comprising:   4. An output switching means for outputting the predetermined serial data during a period of the slave address setting instruction and outputting other information data during a period not corresponding to the period of the slave address setting instruction. The communication apparatus as described in. The predetermined serial data output means is configured to output each of the predetermined serial data corresponding to each of the plurality of slave devices corresponding to each output terminal,
5. A predetermined serial data distribution unit that distributes the predetermined serial data output from the predetermined serial data output unit to the corresponding data input terminal in each of the plurality of slave devices. The communication device according to any one of the above. Communication between devices in which a master device and a plurality of slave devices are connected to a communication line having a serial data line and a clock line, and serial data transfer is performed between the master device and the corresponding slave device through the communication line according to a predetermined communication protocol In a communication device suitable as the slave device in a system ,
For each of the plurality of slave devices connected to the same communication line, the plurality of address setting input terminals more than the combination while minimizing the number of input terminals necessary for external address setting A communication device that enables communication with a slave device of
Determining slave address data representing the communication device with reference to data of a function relationship defined in advance for a predetermined logical value supplied to one or more data input terminals other than the terminal connected to the communication line; Individual slave address determination means for writing the determined slave address data as a specific slave address in a predetermined data holding unit;
Communication control means for performing communication by the individual slave address written in the data holding unit by the individual slave address determination means;
A communication apparatus comprising:

Images