JPH11167548A - Data transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform the effective serial communication according to the load situation, etc., by selecting a communication line in time division to communicate with a prescribed communication IC based on the contents of connection information that is set to a selection register. SOLUTION: A serial communication control part 460 transfers the data of a data register 0 contained in a communication controller 401 to a shift register 122 via a transmission buffer 121. At this time, the part 460 reads out the information on the connection state set at a selection register 462 and decides based on the read information that a communication IC 402 of address 0 is connected to a communication line 410 having a communication IC 403 of address 4 as its termination. Thus, a selector 461 selects the line 410. Then a clock (CLK) and the data (DATA) are outputted to the line 410. The communication is performed with the IC 402 synchronously with the CLK and accordingly the DATA are sent to the IC 402.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission system, and more particularly, to a method of serially transmitting data between a communication control means and a plurality of communication means by selecting a plurality of communication input / output means in a time-division manner. The present invention relates to a data transmission system that performs transmission.

[0002]

2. Description of the Related Art FIG. 11 shows a configuration example of a conventional serial communication system. This serial communication system
A communication controller 101, a communication IC 102 to which a motor driver 105 for driving a motor 104 is connected, and a communication IC 103 to which a plurality of sensors 106 are connected,
+ 5V line as power supply line, GND line,
A synchronous clock (CLK) line for serial communication,
They are cascaded via a set of four signal lines including data (DATA) lines.

One communication controller 101 has a communication I
C can be connected in cascade up to a maximum of 8, and each communication IC
Can specify a unique address (address 0, address 1,...). In FIG. 11, two communication ICs 102, 10
3 are connected. In the communication controller 101,
Eight data registers 0 to 7 are provided. These data registers 0 to 7
Are the unique addresses of the communication ICs (addresses 0 to
7) is selected by the serial communication control unit 120.

Then, such a communication controller 10
1 performs transmission or reception communication with a communication IC corresponding to each data register. At the time of transmission, transmission buffer 1
21, data is transmitted via the shift register 122, and at the time of reception, data is received via the shift register 124 and the reception buffer 123.

FIG. 12 shows an example of a configuration in which the above-described serial communication system is used in an image forming apparatus 1 such as a copying machine.

In FIG. 12, a host CPU 200 and a communication controller 201 are connected to an address bus, a data bus,
Communication in which a bus is connected by a control signal and a communication controller 201 is connected to a communication IC 202 to which a motor driver 208 for driving a motor 206 arranged at an appropriate position in the apparatus is connected, and a motor driver 209 for driving a motor 207 is connected. An IC 203, a communication IC 204 to which a plurality of sensors 210 are connected, and a communication IC 205 to which a plurality of sensors 211 are connected are connected via one signal line. The communication controller 201 and each communication IC 202 are transmitted by a transmission command or a reception command from the host CPU 200.
Data communication is performed between the communication device and the device.

A unique address (address 0, address 1, address 2,...) Is determined for each communication IC irrespective of the arrangement position of these communication ICs 202 to 205 in the device. By designating an address in the frame (pulse train), transmission / reception communication is performed with the communication IC having the corresponding address.

An outline of the operation of the serial communication system will be described. When performing a transmission operation of transmitting predetermined phase data to rotate the motor 206, the host CPU 2
00 sets a transmission flag for performing transmission in the communication controller 201 and writes transmission data to the data register 0. When the transmission data is written, the communication controller 201 sends a pulse train of a predetermined frequency to the CLK line.

With such a system configuration, it is possible to operate a large number of motors and sensors arranged in various parts of the entire apparatus by four cascade-connected signal lines and to read information. In this example, a configuration has been described in which one address is 8 bits and information for 8 addresses is exchanged between the communication controller and the communication IC. However, the configuration is changed to an appropriately optimized configuration according to the communication data format agreement. it can. Further, by providing a plurality of communication controller functions, the number of communication ICs can be increased by increasing the number of signal lines correspondingly.

[0010]

Generally, when the number of communication ICs connected to one set of communication lines is small, the communication ICs are connected to separate communication lines, that is, serial communication is performed in a multi-system connection state. It may be better in terms of processing efficiency.

For example, for a communication IC connected to a load in which delay is not allowed or a high-speed load, it is better to select an address having the highest priority of communication as much as possible. It is better to connect multiple systems for serial communication.

On the other hand, for a communication IC connected to a load to which a certain amount of delay is allowed, the priority of communication is not so important. It is more efficient to perform serial communication by connecting all communication ICs to the communication line in consideration of assembling and the like.

However, in the above-described conventional serial communication system, the number of communication lines is arbitrarily changed according to the number of communication ICs and the load conditions of motors and sensors connected to the communication ICs. It is not possible. As a result, there is a problem that serial communication cannot be performed efficiently.

For example, as shown in FIG.
In a case where only two communication ICs 102 and 103 are used in one unit despite the fact that a maximum of eight communication ICs can be cascade-connected to one set of communication lines, serial communication is performed depending on the load condition. In doing so, it is very inefficient.

Therefore, an object of the present invention is to divide a communication line into one or more systems according to the number of communication ICs connected to the communication line and the load status connected to the communication IC. Another object of the present invention is to provide a data transmission system capable of performing serial communication efficiently.

[0016]

According to the present invention, there is provided a communication control means for controlling serial communication for transmitting and receiving predetermined data in a time series on a data line, and the transmission and reception of the data between the communication control means. A data transmission system comprising a plurality of communication means for performing, a plurality of communication input and output means connected between the communication control means and the plurality of communication means, provided in the communication control means, Communication selection means for selecting the plurality of communication input / output means in a time-division manner, by selecting the plurality of communication input / output means in a time-division manner by the communication selection means, connecting to a predetermined communication means, A data transmission system for serially transmitting data is configured.

Here, the communication control means has a data register for storing communication data corresponding to the plurality of communication means on a one-to-one basis.

The number of bits of the data register may be equal to the number of bits of data that can be handled by the communication means.

The communication selecting means has a select register in which connection information as to which communication input / output means the plurality of communication means corresponding to the data register are connected to is set.

The connection information set in the select register can be determined according to the number of the communication means and / or the load status connected to the communication means.

In the plurality of communication input / output means, only the communication input / output means selected by the communication selection means is provided.
A synchronous clock and a communication pulse train can be input / output.

According to the present invention, there is provided an image forming apparatus for controlling image formation in an image forming unit by a plurality of control units, the apparatus comprising the data transmission system, wherein the communication means of the data transmission system comprises the image forming apparatus. Unit, the communication control unit of the data transmission system is incorporated in the control unit, the communication unit and the communication control unit are connected by the plurality of communication input / output units, and the plurality of communication input / output units are connected by the communication control unit. By selecting the communication input / output means in a time-division manner, an image forming apparatus for serially transmitting data is configured.

Here, the image forming section can be constituted as an electrophotographic image forming section for forming an image by an electrophotographic method.

Further, the present invention is an information processing system for exchanging information between a first information processing apparatus and a second information processing apparatus, comprising the data transmission system,
The communication means of the data transmission system is incorporated in the first information processing device, the communication control means of the data transmission system is incorporated in the second information processing device, and the communication means is provided between the communication means and the communication control means. Are connected by the plurality of communication input / output units, and the communication control unit selects the plurality of communication input / output units in a time-division manner, thereby transmitting data serially, thereby configuring an information processing system.

Further, the present invention is a method for controlling serial communication for transmitting and receiving predetermined data in a time series between a communication control means and a plurality of communication means, wherein the communication control means includes Selecting a data register corresponding to the plurality of communication means in a one-to-one correspondence to transmit data of the plurality of communication means; and connection information indicating which communication input / output means the communication means corresponding to the data register is connected to. In the select register, reading connection information set in the select register, and selecting a plurality of communication input / output units in a time-division manner based on the connection information; Connecting the input / output means to the communication means corresponding to the data register; and communicating the predetermined data serially via the communication input / output means connected to the communication means. By comprising the step of transmitting, to provide a data transmission method.

Here, the connection information set in the select register includes the number of the communication means and / or
It can be determined according to the load situation connected to the communication means.

Only the communication input / output means selected from the plurality of communication input / output means can input / output the synchronization clock and the communication pulse train.

Also, the present invention provides a plurality of communication lines including a first communication line for communicating with one or more communication devices and a second communication line for communicating with one or more communication devices. Switching means for switching to any one of the above, storage means for storing information for recognizing which communication device is connected to which communication line, and the storage means for connecting to a communication device to perform communication. Switching control means for controlling the switching means based on information stored in the means, and communication means for communicating with one or a plurality of communication devices on a communication line switched by the switching means. Thus, a communication device is configured.

Here, the communication means can perform serial communication.

[0030] The communication line may include a clock signal line and a data signal line.

A plurality of communication devices on the communication line can be cascaded.

Each of the plurality of communication devices has an address, and the communication means can transmit data indicating an address of a communication device with which communication is to be performed via a communication line which is switched by the switching control means. .

A motor or a sensor is connected to the communication device in each of the pits on the communication line, and the communication means controls driving of the motor by transmitting data to the communication device to which the motor is connected. Then, by receiving data from the communication device to which the sensor is connected, the detection result of the sensor can be input.

Each of the plurality of communication devices has an address, and the storage means can store information indicating which address of the communication device is connected to the first communication line.

[0035] The storage means can store connection information written from the another device at the time of initializing another device.

The storage means can store connection information stored in advance in the control section of the image forming apparatus when the image forming apparatus is powered on.

The communication line has a register corresponding to each of a plurality of communication devices, and each register can store data to be transmitted to each communication device and data received from each communication device.

Further, the present invention provides a switch for switching between a first communication line for communicating with one or more communication devices and a second communication line for communicating with one or more communication devices. Means, storage means for storing information for recognizing which communication device is connected to which communication line, and information stored in the storage means for connection to a communication device to be communicated. A communication device comprising: a switching control unit that controls the switching unit based on the communication unit; and a communication unit that communicates with one or a plurality of communication devices on a communication line switched by the switching unit. I do.

[0039]

Embodiments of the present invention will be described below in detail with reference to the drawings.

First, the first embodiment of the present invention will be described with reference to FIG.
6 to FIG. 9, FIG. 9, and FIG. FIG.
1, the description of the same parts as those of FIG. 12 is omitted, and the same reference numerals are used for the same parts.

FIG. 1 shows a schematic configuration of a serial communication system according to the present invention. The serial communication system is configured, for example, as an electrophotographic image forming apparatus such as a copying machine, or as an information processing system for exchanging information data between a plurality of information processing apparatuses (for example, personal computers). be able to. Hereinafter, in this example, an example in which the image forming apparatus is configured as an image forming apparatus will be described.

The units A to C are built in the image forming apparatus. The unit A is configured as a control unit of the apparatus main body, and controls serial communication with each unit after the unit B. Unit B includes communication IC 402 (address 0) to communication IC
403 (address 4) are provided (communication ICs of addresses 1 to 3 are not shown). Unit C includes communication IC 404 (address 5) to communication I as communication means.
C405 (address 7) are provided (the communication IC at address 6 is not shown).

Each of the communication ICs 402 and 403 has a motor 42 disposed at an appropriate place in the apparatus (for example, a paper feeding unit or a paper conveying unit).
1, 423 are connected to motor drivers 420, 422. The communication ICs 404 and 405 include:
A plurality of sensors 424 and 425 arranged at appropriate places in the apparatus (for example, around a sheet feeding cassette and a photosensitive drum) are connected. The combination of motors, sensors, and the like connected to each of the communication ICs 402 to 405 is not limited to the configuration of this example.

Communication units 410 and 411 as communication input / output means are provided between unit A including communication controller 401 and unit B including communication ICs 402 to 403 and unit C including communication ICs 404 to 405.
Connected by These two communication lines 41
0,411 is + 5V line 450, GND line 45
1. Clock (CLK) line 453, data (DAT)
A) Each is connected by a line 452.

Here, the internal configuration of the unit A according to the present invention will be described. In this unit A, a host CPU 200 for controlling the image forming apparatus and data (DA)
A communication controller 401 as communication control means for controlling serial communication for transmitting or receiving predetermined data in a time series on a TA) line 452 is provided. The host CPU 200 is connected to the communication controller 401 via a bus, and exchanges communication commands and data with the communication controller 401.

The communication controller 401 includes data registers 0 to 7, a serial communication control unit 460, a selector 461, a transmission buffer 121, and a shift register 1.
22, a reception buffer 123, and a shift register 124
And The data registers 0 to 7 store the communication I
C402 (address 0) to communication IC 405 (address 7) are configured in one-to-one correspondence.

The serial communication control section 460 has a select register 462 shown in FIG. In the select register 462, the communication ICs 402 to 405 corresponding to the data registers 0 to 7 store which communication lines 410 and 41.
1 is set as information on the connection state of the connection. The information set in the select register 462 is determined according to the number of communication ICs and the load status of the communication ICs, is programmed in advance in the host CPU 200, and is set in the initial state (when the image forming apparatus is powered on). It is set by the CPU 200. As described above, since the host CPU 200 sets the connection information in the select register 462 at the time of the initial setting, no matter what connection relationship the communication IC connected to the communication lines 410 and 411 is applied to the device, The controller 401 may be the same, and the versatility of the communication controller 401 is improved, and the cost can be reduced. Here, information regarding the connection state set in the select register 462 will be described. When the number of communication ICs connected to one set of communication lines is large, information for selecting all the communication ICs connected to the one set of communication lines is set, and the number of communication ICs connected to one set of communication lines is set. When the number of communication ICs to be used is small, information for selecting communication ICs connected to multi-system communication lines is set.

Then, based on the set information,
The selector 461 selects the communication lines 410 and 411. The selector 461 and the select register 462 in FIG. 2 constitute a communication selection unit 463 for selecting the two communication lines 410 and 411 in a time-division manner. Thereby, the communication controller 401 sets each data register 0
The communication for transmission or reception is performed with respect to the communication ICs 402 to 405 corresponding to.

FIG. 2 shows the structure of the select register 462 in the communication controller 401. The select register 462 includes a communication IC connected to the communication line 410.
Information on the end addresses 402 to 403 is set. Therefore, the address of the communication IC connected to the communication line 410 or the communication line 411 is automatically determined according to the information content set in the select register 462.

For example, the select register 462 shown in FIG.
Is set to “00000100” (end address information = 4). Thereby, the communication line 410
Has five communication ICs from address 0 to address 4.
It can be seen that 402 to 403 are connected. Accordingly, it can be seen that three communication ICs 404 to 405 from address 5 to address 7 are connected to the communication line 411.

Next, the communication controller 401
A data transmission operation and a data reception operation performed on C402 will be described.

First, the communication controller 401
An example in which a data transmission operation is performed on C402 will be described. When the transmission flag is set by the host CPU 200 and data is written to the data register 0, the serial communication control unit 460 selects the data register 0 corresponding to the communication IC 402. At this time, the select register 462 already has the communication IC 402 of the address 0 corresponding to the data register 0 as shown in FIG.
Is set to determine which communication line is connected to (end address information).

Then, the serial communication control unit 460 transfers the data of the data register 0 in the communication controller 401 to the shift register 12 via the transmission buffer 121.
Transfer to 2. At this time, the serial communication control unit 460
Reads the information on the connection state set in the select register 462, and in accordance with the read information on the connection state, the communication IC 402 of the address 0 stores the address 4
It is determined that the communication line 410 is connected to the communication line 410 ending with the communication IC 403, and the selector 461 selects the communication line 410. A clock (CLK) and data (DATA) are output to the communication line 410.
Data is transmitted to the communication IC 402 by communicating with the communication IC 402 in synchronization with the clock output.
Thereby, the motor driver 420 controls the driving of the motor 421 based on the transmitted data. At this time, there is no clock and no data output on the communication line 411.

Next, the communication I
The operation of transmitting data to be written to C402 will be described in detail.

The communication controller 401 and the communication IC 402 perform data transmission processing in the data register 0 according to the transmission data format shown in FIG. 9 in synchronization with the clock (CLK) output from the communication controller 401.

In FIG. 9, first, the communication controller 4
01 at the first falling edge of CLK sent from
C402 recognizes the start of communication, and sets the start bit (ST) (representing the top of the frame) of the start bit (ST) on the DATA line by the communication controller 401 at the next rise of CLK.
Check whether "L" has been transmitted.

The communication IC 402 determines whether to perform the transmission operation (“L”) or the reception operation (“H”) based on the next falling edge of CLK. The data for the next three clocks is an address bit.
01 transmits a designated address on the DATA line, and if this address is its own address, the communication IC 402 takes in a total of 8 bits of data (D7 to D0) on the DATA line transmitted from the next CLK. .

The communication IC 402 captures the parity data (PA) sent from the communication controller 401 at the next falling edge of CLK at the rising edge of the CLK, and adds the parity data (PA) calculated by itself from the data (D7 to D0). Compare. If the parities match, the data (D7 to D0) is validated, and the communication controller 40
ACK ("L") is transmitted to the communication controller 401, and if the parities do not match, ACK ("H") is transmitted to the communication controller 401 to invalidate the data (D7 to D0).

The communication controller 401 receives ACK at the rise of CLK, and if ACK is “L”,
Stop bit (SP) at next falling edge of CLK
"L" is sent, and if ACK is "H", a stop bit (SP) "H" is sent at the next falling edge of CLK. The designated communication IC recognizes the stop bit (SP) at the rising edge of CLK, and determines the stop bit (S
If P) is "L", data is output, and if the stop bit (SP) is "H", no data is output. Communication is performed with the communication IC 402 in the above sequence, and the motor 421 is rotated.

An example in which the communication controller 401 performs a receiving operation on the communication IC 404 following the transmission operation of the communication IC 402 will be described.

Now, in the select register 462, information (end address information) to which communication line the communication IC 404 corresponding to the data register 5 is connected is set. When the reception flag is set by the host CPU 200, the serial communication control unit 460 reads the information on the connection state set in the select register 462, and sets the communication line 411 to the selector 461 according to the read information on the connection state. select. Clock (CLK) and data (DATA) are output to the selected communication line 411. By communicating with the communication IC 404 in synchronization with the clock output, data detected by the sensor 424 of the communication IC 404 is received by the communication controller 401. The received data is transferred to the data register 5 via the shift register 124 and the reception buffer 123. At this time, the communication line 410 has no clock and no data output.

Next, the communication controller 401
The details of the data reception operation for reading data from 404 will be described.

In synchronization with the clock output from the communication controller 401, the communication controller 401 and the communication IC 404 perform processing according to the reception data format shown in FIG.

In FIG. 10, first, the communication IC 404 recognizes the start of communication at the first fall of CLK sent from the communication controller 401, and the communication controller 401 sets a start bit (ST) on the DATA line at the next rise of CLK. It is confirmed whether or not "L" is transmitted. The communication IC 404 determines whether to perform the transmission operation (WR) (“L”) or the reception operation (RD) (“H”) based on the next falling edge of CLK.

The data for the next three clocks are address bits, and the communication controller 401 sends out a specified address on the DATA line. The communication IC 404 captures this address, and if it is its own address, sends the sensor data to the communication controller 401 from the next CLK. The specified communication IC 404 sends a total of 8 bits of data (D0 to D7) onto the DATA line from the falling edge of CLK, and the communication controller 401
The data (D0 to D7) is taken in at the fall of LK. The communication controller 401 causes the parity data (P
A) is fetched and compared with the parity data calculated by itself from the data (D0 to D7). If the parities match, the data (D0 to D7) is made valid. If the parities do not match, the data (D0 to D7) is made invalid. Communication is performed with the communication IC 404 in the above sequence, and the value of the sensor 424 is read.

As can be seen from the transmission operation and the reception operation described above, the process of controlling the selection of the communication lines 410 and 411 based on the information set in the select register 462, which is performed in the serial communication control unit 460, is performed by time division. Will be That is, in the above example, first, the communication line 4
10 is selected, and the communication line 411 is selected for the operation of receiving the address 5. Such line selection is performed in a time-division manner based on the information set in the select register 462. As described above, the information set in the select register 462 for determining the line selection order is determined according to the number of communication ICs and the load status connected to the communication ICs. When eight communication ICs are connected to the communication line 410 as shown in FIG. 3, the selection register 462 is set as shown in FIG.

Next, an example in which three communication lines are provided as shown in FIG. 5 will be described. 3 communication lines
In this case, as shown in FIG.
Increase the number of 0,471 by 1 byte. Thus, the communication IC connected to the three communication lines is determined, and the clock and the pulse train are output only to the target communication line.

For example, the select register 4 shown in FIG.
70 is “00000010” (end address information =
2) is set, and “00000101” (end address information =
It is assumed that 5) is set. The three communication lines are referred to as communication lines A, B, and C, respectively. Thereby, the communication IC connected to the communication line A has the address 0
To the address 2, the communication IC connected to the communication line B is from the address 3 to the address 5, and the communication IC connected to the communication line C is from the address 6 to the address 7. As described above, even when a plurality of communication lines are provided, communication can be performed by increasing the number of select registers having connection information.

Next, a second embodiment of the present invention will be described with reference to FIG.
A description will be given with reference to FIG. The description of the same parts as in the first embodiment is omitted, and the same reference numerals are given.

In this example, a case where two communication lines are provided will be described. FIG. 7 shows a schematic configuration of a serial communication system according to the present invention. The unit A including the communication controller 701, the unit B including the communication ICs 702 to 705, and the unit C including the communication ICs 706 to 709 include a + 5V line 450, a GND line 451, a clock (CLK) line 453, and a data (DATA) line 452. Are connected to each other.

The communication controller 701 includes communication ICs 702 (address 0) to
Communication is performed with the communication IC 709 (address 7).
At that time, it has the priority of communication. In this example, communication is prioritized as the address is lower.

When communication requests to a plurality of communication ICs overlap, communication is performed in accordance with the priority order, so that the lower the communication priority, the longer the communication waits. As a communication IC that leads to a load in which delay is not allowed or a load with a high speed, an address having a high communication priority is selected. Each communication IC 702 to communication I
Motors and sensors as described in the first embodiment are connected to C709, but the description in this example is omitted.

FIG. 8 shows a select register 7 provided in the serial communication control unit 710 of the communication controller 701.
11 shows a configuration example. The connection to the communication line 410 or the communication line 41
1 is determined. In this example, “10101010” is set in the select register 711. With these settings, addresses 0, 2, 4, 6
Are connected to the communication line 410, and the addresses 1, 3, 5,
7 is connected to the communication line 411.

Since the communication is prioritized as the address becomes lower (address 0 has the highest priority), the processing order when the communication requests overlap is as follows: the communication IC 702 (address 0), the communication IC 706 (address 1), Communication IC 703
(Address 2), communication IC 707 (address 3), ...
The order is the communication IC 709 (address 7). In this case, the communication line is stored in the select register 711 for the same reason as described in the first embodiment.
Information is set in order from the highest priority of C, that is, the communication line 410, the communication line 411, the communication line 410, the communication line 411,.

Next, the communication controller 701 sets the communication I
An example in which a transmission operation of writing data to C702 (address 0) is performed will be described.

When the transmission flag is set by the host CPU 200 and the transmission data is written in the data register 0, the serial communication control unit 710 sets the communication IC 702
Select the data register 0 corresponding to. At this time, in the select register 711, information as to which communication line the communication IC 702 corresponding to the data register 0 is to be connected to is set. The 0th bit of the select register 711 indicates that the communication IC 702 at the address 0 is connected to the communication line 410 side.

Then, the serial communication control unit 710 transfers the data of the data register 0 in the communication controller 701 to the shift register 12 via the transmission buffer 121.
Transfer to 2. At this time, the serial communication control unit 710
Reads predetermined information set in the select register 711. The selector 461 selects the communication line 410 according to the read information of the select register 711. The clock and the data are output to the selected communication line 410. By communicating with the communication IC 702 in synchronization with the clock output, data from the data register 0 is transmitted to the communication IC 702. At this time, the communication line 411 does not output clock and data.

Next, the communication controller 701 sets the communication I
An example in which a reception operation of reading data from C709 (address 7) is performed will be described.

Now, in the select register 711, information on which communication line the communication IC 709 corresponding to the data register 7 is to be connected to is set. The serial communication control unit 710 reads out predetermined information set in the select register 711. Then, the selector 461 selects the communication line 411 according to the read information of the select register 711. The clock and data are output to the selected communication line 411. By communicating with the communication IC 709 in synchronization with the clock output, data from the communication IC 709 is received by the communication controller 701. The received data is transferred to the data register 7 via the shift register 124 and the reception buffer 123. At this time, the communication line 410 does not output a clock and a pulse train.

Further, even when a plurality of communication lines are provided,
Communication is possible by increasing the number of select registers having information on which communication line the communication IC corresponding to each of the data registers 0 to 7 is connected to.

The present invention can be applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, and a printer).
The present invention may be applied to an apparatus including two devices (for example, a copying machine and a facsimile machine).

Further, it is needless to say that the present invention can be applied to a case where the present invention is achieved by supplying a program to a system or an apparatus. Then, a storage medium storing a program represented by software for achieving the present invention is supplied to a system or an apparatus, and the computer (or CPU or M) of the system or apparatus is supplied.
(PU) reads out and executes the program code stored in the storage medium, so that the effects of the present invention can be enjoyed.

In this case, the program code itself read from the storage medium implements the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

Examples of the storage medium for supplying the program code include a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, and CD.
-R, magnetic tape, nonvolatile memory card, ROM
(A mask ROM, a flash EEPROM, or the like) can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) running on the computer based on the instruction of the program code. ) May perform some or all of the actual processing, and the processing may realize the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into the memory provided in the function expansion port inserted into the computer or the function expansion unit connected to the computer, the program code is read based on the instructions of the program code. It goes without saying that the CPU included in the function expansion board or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

[0087]

As described above, according to the present invention,
A plurality of communication lines are prepared, the communication line is selected in a time-division manner according to the content of the connection information set in the select register, and communication with a predetermined communication IC is performed. When there are many communication ICs, communication is performed by connecting all the communication ICs to the communication line.
When the number of communication ICs connected to a set of communication lines is small, the communication IC can be connected to another communication line to perform multi-system communication.
A communication line can be selected and changed in a time-sharing manner according to the load status of a motor, a sensor, or the like connected to C, and a system for efficiently performing serial communication can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of a serial communication system in an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a configuration example of a select register.

FIG. 3 is a block diagram illustrating another configuration example of the serial communication system.

FIG. 4 is an explanatory diagram showing another configuration example of the select register.

FIG. 5 is a block diagram showing another configuration example of the serial communication system.

FIG. 6 is an explanatory diagram showing another configuration example of the select register.

FIG. 7 is a block diagram illustrating a configuration example of a serial communication system in an image forming apparatus according to a second embodiment of the present invention.

FIG. 8 is an explanatory diagram showing a configuration example of a select register.

FIG. 9 is an explanatory diagram showing a configuration example of a frame at the time of data transmission.

FIG. 10 is an explanatory diagram showing a configuration example of a frame at the time of data reception.

FIG. 11 is a block diagram illustrating a configuration example of a serial communication system before application of the present invention.

FIG. 12 is a block diagram illustrating a configuration example of a serial communication system in an image forming apparatus before application of the present invention.

[Explanation of symbols]

 401 communication control means 402 to 405 communication means 410, 411 communication input / output means 462 select register 463 communication selection means 701 communication control means 702 to 709 communication means 711 select register 712 communication selection means

Claims (23)

[Claims] 1. A communication control means for controlling serial communication for transmitting and receiving predetermined data in a time series on a data line; and a plurality of communication means for transmitting and receiving the data to and from the communication control means. A data transmission system comprising: a plurality of communication input / output units connected between the communication control unit and the plurality of communication units; and a plurality of communication input / output units provided in the communication control unit. Communication selecting means for selecting the plurality of communication input / output means in a time sharing manner by the communication selecting means, thereby connecting to predetermined communication means and serially transmitting the data. And a data transmission system. 2. The data transmission system according to claim 1, wherein said communication control means has a data register for storing communication data corresponding to said plurality of communication means on a one-to-one basis. 3. The data transmission system according to claim 2, wherein the number of bits of said data register is equal to the number of bits of data that can be handled by said communication means. 4. The communication selecting means, wherein a plurality of communication means corresponding to the data register have a selection register in which connection information as to which communication input / output means is connected is set. Item 3. The data transmission system according to Item 2. 5. The connection information set in the select register is determined according to the number of the communication units and / or a load state connected to the communication units. Data transmission system. 6. A communication clock input / output means for inputting / outputting a synchronous clock and a communication pulse train only to the communication input / output means selected by the communication selection means in the plurality of communication input / output means. The data transmission system according to any one of the above. 7. An image forming apparatus for controlling image formation in an image forming unit by a plurality of control units, comprising: the data transmission system according to claim 1; Incorporating a communication unit into the image forming unit; incorporating the communication control unit of the data transmission system into the control unit; connecting the communication unit and the communication control unit with the plurality of communication input / output units; An image forming apparatus, wherein data is serially transmitted by selecting a plurality of communication input / output units in a time division manner by a communication control unit. 8. The image forming apparatus according to claim 7, wherein the image forming unit is an electrophotographic image forming unit that forms an image by an electrophotographic method. 9. An information processing system for exchanging information between a first information processing device and a second information processing device, comprising: the data transmission system according to claim 1; The communication unit of the data transmission system is incorporated in the first information processing apparatus, and the communication control unit of the data transmission system is
By connecting the communication means and the communication control means by the plurality of communication input / output means, and selecting the plurality of communication input / output means by time division by the communication control means. And an information processing system for transmitting data serially. 10. A method for controlling serial communication for transmitting and receiving predetermined data in a time series between a communication control unit and a plurality of communication units, wherein the communication control unit transmits the predetermined data. Selecting a data register corresponding to the plurality of communication means on a one-to-one basis, and connecting information indicating to which communication input / output means the communication means corresponding to the data register is connected to the select register. Setting, reading connection information set in the select register, and selecting a plurality of communication input / output means in a time-division manner based on the connection information; and Connecting to the communication means corresponding to the data register; and serially transmitting the predetermined data via communication input / output means connected to the communication means. And a data transmission method comprising the steps of: 11. The connection information set in the select register is determined according to the number of the communication units and / or a load situation connected to the communication units. Data transmission method. 12. The data transmission according to claim 10, wherein only a communication input / output unit selected from the plurality of communication input / output units inputs / outputs a synchronization clock and a communication pulse train. Method. 13. One of a plurality of communication lines including a first communication line for communicating with one or more communication devices and a second communication line for communicating with one or more communication devices. Switching means for switching; storage means for storing information for recognizing which communication device is connected to which communication line; and storage means for connecting to a communication device to be communicated. Switching control means for controlling the switching means based on the received information; and 1 on the communication line switched by the switching means.
A communication device comprising communication means for communicating with any one of a plurality of communication devices. 14. The communication device according to claim 13, wherein said communication means performs serial communication. 15. The communication device according to claim 13, wherein said communication line includes a clock signal line and a data signal line. 16. The communication device according to claim 13, wherein a plurality of communication devices on the communication line are cascaded.
The communication device as described. 17. The communication device according to claim 1, wherein each of the plurality of communication devices has an address, and the communication unit transmits data indicating an address of the communication device to perform communication via a communication line that is switched and controlled by the switching control unit. 14. The communication device according to claim 13, wherein: 18. A motor or a sensor is connected to a communication device of each shaft on the communication line, and the communication means transmits data to a communication device to which the motor is connected, thereby driving the motor. And receiving data from a communication device to which the sensor is connected and inputting a detection result of the sensor.
3. The communication device according to 3. 19. The plurality of communication devices each have an address, and the storage unit stores information indicating which address of the communication device is connected to the first communication line. The communication device according to claim 13, wherein 20. The communication device according to claim 13, wherein said storage means stores connection information written from said another device at the time of initializing another device. 21. The communication apparatus according to claim 13, wherein said storage unit stores connection information stored in a control unit of said image forming apparatus when said image forming apparatus is powered on. 22. A communication apparatus having a register corresponding to each of a plurality of communication devices on the communication line, wherein each register stores data to be transmitted to each communication device and data received from each communication device. The communication device according to claim 13, wherein: 23. Switching means for switching to one of a first communication line for communicating with one or a plurality of communication devices and a second communication line for communicating with one or a plurality of communication devices. Storage means for storing information for recognizing which communication device is connected on the communication line; and, based on the information stored in the storage means, for connecting to a communication device to perform communication. Switching control means for controlling the switching means; and 1 on the communication line switched by the switching means.
A communication device comprising communication means for communicating with any one of a plurality of communication devices.