KR20220082533A - Serial communication apparatus and method - Google Patents

Abstract

A device and a communication method are provided in which a greater number of slave devices can be connected to a master device for serial communication. A serial communication device according to an embodiment of the present invention includes: a plurality of slave devices for performing serial communication by forming a plurality of communication lines with a master device; and transmits a clock signal to the plurality of slave devices through a Chip Select (CS) communication line commonly used by the plurality of slave devices, and transmits operation target data for communication with any one of the plurality of slave devices. Output Slave Input) transmits to the plurality of slave devices through a communication line, and identifies a slave device that responds based on a result value calculated using the clock signal and calculation target data as a communication target device, and the identified and the master device communicating with the slave device. The slave device may check whether the clock signal is abnormal by checking whether a frequency of the clock signal received through the CS communication line is included in a preset frequency range.

Description

SERIAL COMMUNICATION APPARATUS AND METHOD

The present invention relates to a serial communication device and method that is easy to expand. More particularly, it relates to a device and a communication method capable of serial communication by connecting a greater number of slave devices to a master device.

SPI (Serial Peripheral Interface) is a method of performing full-duplex synchronous communication using four communication lines. The SPI is divided into a master device and a plurality of slave devices, and the master device forms four communication lines with the slave device. That is, there are four communication lines between the master device and the slave device: a CS (Chip Select) communication line, an SCK (SPI Clock) communication line, a MOSI (Master Output Slave Input) communication line, and a MISO (Master Input Slave Output) communication line. is formed

The SCK communication line, the MOSI communication line, and the MISO communication line may be commonly used in a plurality of slave devices. However, the CS communication line is connected only to the master device and one slave device and is used as an independent dedicated line. Accordingly, as many CS communication lines as the number of slave devices must be established.

However, when adding a new slave device, if the CS communication line that can be connected from the master device is insufficient, there is a problem that additional slave devices cannot be connected. In this case, it is necessary to change the design of the master device, such as adding a new CS pin to the master device. However, such a design change of the master device requires a lot of time and money.

Korea Patent Publication No. 10-2001-0084862 (2001.09.06)

The technical problem to be solved by the present invention is to provide a serial communication device and method capable of serial communication by connecting a greater number of slave devices to the master device without changing the physical design of the master device.

Another technical problem to be solved by the present invention is to provide a serial communication device and method for stably performing serial communication by verifying an error in a clock signal of a master device.

Another technical problem to be solved by the present invention is to provide a serial communication device and method for performing serial communication without data collision even when a CS communication line is commonly used.

The technical problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

In order to solve the above technical problem, a serial communication device according to an embodiment of the present invention includes: a plurality of slave devices for performing serial communication by forming a plurality of communication lines with a master device; and transmits a clock signal to the plurality of slave devices through a Chip Select (CS) communication line commonly used by the plurality of slave devices, and transmits operation target data for communication with any one of the plurality of slave devices. Output Slave Input) transmits to the plurality of slave devices through a communication line, and identifies a slave device that responds based on a result value calculated using the clock signal and calculation target data as a communication target device, and the identified It may include the master device communicating with the slave device.

In an embodiment, the slave device may check whether the clock signal is abnormal by checking whether a frequency of the clock signal received through the CS communication line is included in a preset frequency range.

In another embodiment, the slave device may check whether the clock signal is abnormal by dividing the clock signal and checking whether the divided clock signal is included in the preset frequency range.

In some embodiments, when an abnormality of the clock signal is checked, the slave device may transmit a code indicating a clock error to the master device through a Master Input Slave Output (MISO) communication line.

The slave device may communicate with the master device in response to the master device when the operation target data is calculated using a preset logical operator and the calculated result matches the retained information.

The master device may transmit a clock signal to the plurality of slave devices and transmit the operation target data to the plurality of slave devices during a device selection period for establishing communication.

In a method for a slave device to perform serial communication with a master device according to another embodiment of the present invention for solving the above technical problem, a clock signal is received from the master device through a CS (Chip Select) communication line, and MOSI (Master Output Slave Input) receiving operation target data from the master device through a communication line; obtaining operation target data received through the MOSI communication line based on the clock signal, and obtaining an operation result value based on the operation target data; and performing communication with the master device when the result of the calculation matches information being stored in advance.

1 is a diagram illustrating a serial communication device according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a communication line formed between the master device and the slave device disclosed in FIG. 1 .
3 is a diagram illustrating calculation target data and calculation results.
4 is a diagram illustrating a signal generated in each communication line.
5 is a diagram illustrating an abnormally confirmed clock signal.
6 is a flowchart illustrating a method of performing serial communication in a slave device according to another embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Advantages and features of the present invention, and a method for achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments published below, but may be implemented in various different forms, and only these embodiments allow the publication of the present invention to be complete, and common knowledge in the technical field to which the present invention pertains It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used with the meaning commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not to be interpreted ideally or excessively unless clearly defined in particular. The terminology used herein is for the purpose of describing the embodiments and is not intended to limit the present invention. In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase.

Hereinafter, some embodiments of the present invention will be described with reference to the drawings.

1 is a diagram illustrating a serial communication device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a communication line formed between the master device and the slave device disclosed in FIG. 1 .

1 and 2, the serial communication device 100 according to an embodiment of the present invention may include at least one master device 110 and a plurality of slave devices 120-N, The master device 110 and the plurality of slave devices 120 -N may perform SPI-based serial communication. The master device 110 may select a slave device 120 -N with which to communicate, and may perform serial communication with the selected slave device 120 -N.

A plurality of communication lines may be formed between the master device 110 and each of the slave devices 120 -N. As a plurality of communication lines, four communication lines may be formed between the master device 110 and the slave device 120 -N. As an embodiment, a CS (Chip Select) communication line as a first communication line, a MOSI (Master Output Slave Input) communication line as a second communication line, a MISO (Master Input Slave Output) communication line as a third communication line, and a fourth communication line As a communication line, an SCK (SPI Clock) communication line may be formed between the master device 110 and the slave device 120 -N.

Each of the MOSI communication line, the MISO communication line, and the SCK communication line is branched to each slave device 120-N, and each of the slave devices 120-N can use it in common.

The MOSI communication line is a communication line through which data transmitted from the master device 110 and received by the slave device 120-N passes.

The MISO communication line is a communication line through which data transmitted from the slave device 120-N and received by the master device 110 passes.

The SCK communication line is a communication line through which the SPI clock signal for synchronizing data transmitted and received between the MOSI communication line and the MISO communication line passes. The SPI clock signal may not be generated during the device selection period to be described later, but may be generated in the master device 110 during the data transmission period and transmitted to each slave device 120 -N. Here, the device selection period is a time for selecting the slave device 120-N before actual data is transmitted, and the process according to the device selection before the data transmission period is performed between the master device 110 and the slave device 120-N. ) can progress between

When the CS communication line is not used for slave extension, the CS communication line can be used exclusively for a specific slave device 120 -N. On the other hand, when the CS communication line is used for expansion, the CS communication line is branched into a plurality of slave devices 120 -N and can be commonly used by two or more slave devices 120 -N.

2 as an example, each of the first slave device 120-1 and the second slave device 120-2 does not share a CS communication line and masters a dedicated CS communication line that can only be used by itself. It can be formed with the device 110 . Meanwhile, the third slave device 120 - 3 and the fourth slave device 120 - 4 share a CS communication line. That is, the CS communication line formed in the third channel in the master device 110 may be branched at point a and also connected to the fourth slave device 120 -N. A CS communication line used for slave extension and shared by a plurality of slave devices 120-3 and 120-4 is exemplified by reference numeral 11 in FIG. 2 . In other words, in FIG. 2 , the CS communication line used exclusively by the first slave device 120-1 and the second slave device 120-2 is not used for expansion, but in the third slave device 120-3 The used CS communication line 11 is used for expansion by being shared with the fourth slave device 120-4.

In the past, as many slave devices as the number of dedicated CS communication lines could be connected, according to this embodiment, the SCK communication line, the MOSI communication line, and the MISO communication line, in which the additional slave devices are already formed, are connected to use the three communication lines in common. Instead, the CS communication line can also be used in common. Accordingly, the CS communication line can be branched to a plurality of slave devices 120-N, so that a greater number of slave devices 120-N can be connected to the master device 110 without creating additional pins in the master device 110 . ) can be connected.

In order to select any one of the slave devices sharing one CS communication line 11, the master device 110 performs an operation to specify a clock signal for operation and a communication target to the slave device 120-N. Target data can be transmitted. In one embodiment, when a plurality of slave devices 120-3 and 120-4 share one CS communication line, the master device 110 operates through the CS communication line 11 during the device selection period. A clock signal for , may be transmitted to the third slave device 120 -N and the fourth slave device 120 -N. In addition, the master device 110 checks a slave device selected as a communication target among the third slave device 120-N and the fourth slave device 120-N, and checks the calculation target data related to the selected slave device. , the operation target data may be transmitted to each slave device 120 -N through the MOSI communication line. The calculation target data may be data related to deriving a result value consistent with information held by the selected slave device. The operation target data may be a plurality of bits corresponding to a predetermined number. In proportion to the number of bits, the number of expandable slave devices 120 -N may also increase.

The master device 110 identifies the slave device 120-N responding based on the clock signal for the calculation and the calculation target data as the communication target device, and the identified slave device 120-N and SPI based serial communication can be performed. The response may be received through the MISO communication line, and may be a result value calculated by the slave device 120-N based on the operation target data. The master device 110 verifies whether the result value is correct, communicates with the slave device 120-N that has transmitted the response if it is correct, and transmits the response if the response is not correct. It is determined that a failure has occurred in N), and communication with the slave device 120 -N may be suspended. The master device 110 may be a processor such as a microcontroller unit (MCU).

Meanwhile, the master device 110 may receive an error code indicating that there is an error in the clock signal from the slave device 120 -N through the MISO communication line. In this case, the master device 110 may determine that an error has occurred in the serial communication device 100 and output an error message. In this case, the master device 110 may output an error message to a display means or the like.

When the master device 110 communicates with the responding slave device 120-N, it transmits the SPI clock to each slave device 120-N through the SCK communication line, and the corresponding slave device through the MOSI communication line. Data can be transmitted to (120-N) and received from the corresponding slave device (120-N) through the MISO communication line.

When a clock signal is generated from the CS communication line, the slave devices 120-3 and 120-4 using the CS communication line 11 in common recognize that the device selection period is in progress, and the operation target data received through the MOSI communication line. may be checked, and a result may be obtained by performing an operation based on the operation target data. As an embodiment, the slave device 120 -N may obtain the result value by performing an operation by substituting the operation target data into a preset operation method. The operation target data may be a predetermined number of bits, and the operation method may be an operation method using one or more logical operators. In the calculation method, the previously stored data and the calculation target data may be calculated by the one or more logical operators. As the logical operator, one or more of XOR, OR, AND, NOR, and the like may be used.

3 is a diagram illustrating calculation target data and calculation results.

As illustrated in FIG. 3 , the calculation result value may vary according to the value of the calculation target data. That is, calculation result values may be different depending on the calculation target data. The calculation method may be set so that different calculation results may appear according to calculation target data.

3 as an example, if the calculation target data is '000', the slave device 120-N may obtain '011' as the calculation result value, and when the calculation target data is '101', The slave device 120 -N may obtain '010' as a result of the operation.

The slave device (120-N) checks whether the operation result matches the information already held, and if it matches, transmits a response to the master device 110 using the MISO communication line, and communicates with the master device 110 can be performed. At this time, the slave device 120-N is synchronized with the master device 110 through the SPI clock received through the SCK communication line, and receives data from the master device 110 through the MOSI communication line, and MISO communication Data may be transmitted to the master device 110 through the line. The slave device 120 -N may be a power semiconductor, a driving semiconductor, a sensor semiconductor, an electrically erasable programmable ROM (EEPROM), or the like.

On the other hand, the slave device 120 -N may not respond to the master device 110 without transmitting a response to the master device 110 if the calculation result does not match the information already held. In this case, the slave device 120 -N may ignore data received from the master device 110 through the MOSI. The matching may mean that the calculated result value matches the information held by the slave device 120 -N or corresponds to a part of the held information.

In an embodiment, the retained information may be identification information of the slave device 120-N, and when the calculated result value matches its own identification information, the slave device 120-N uses the MISO communication line Through , a response may be transmitted to the master device 110 .

In some embodiments, the slave device 120-N may transmit the calculated result value to the master device 110 as the response. In this case, the master device 110 responds to the calculated result value. If the verification is performed and the verification is successful, serial communication with the master device 110 may be performed.

4 is a diagram illustrating a signal generated in each communication line.

In FIG. 4, reference numeral 'T1' exemplifies a section corresponding to the device selection period. As illustrated in FIG. 4 , during the device selection period T1 , a clock signal may be generated on the CS communication line through the master device 110 , and a predetermined number of bits of operation target data may be generated on the MOSI communication line. can

Also, during the device selection period T1 , a response of a predetermined number of bits may occur in the MISO communication line through the slave device 120 -N as a communication target. The response may be a result value calculated by the slave device 120 -N.

As shown in FIG. 4, among all clocks generated during the data transmission period, from the first rising edge to the third rising edge of the front part is set as a section for MOSI, and from the fourth rising edge to the sixth rising edge Up to the edge can be set as a section for MISO.

The slave device 120 -N and the master device 110 sharing the CS communication line may synchronize timing by checking data at the timing of a rising edge of a clock. That is, the slave device 120-N sharing the CS communication line can check the bits corresponding to the operation target data at the rising edge timing, and the master device 110 can check the bits corresponding to the response at the rising edge timing. have. In FIG. 4, it is exemplified that the bit string '101' is generated in the MOSI communication line as the operation target data, and the bit string '001' is generated in the MISO as a response to the operation target data.

The slave device 120-N checks the frequency of the clock signal received through the CS communication line during the device selection period T1, and checks whether the frequency of the clock signal is included in a preset frequency range. You can check for any abnormalities. The slave device 120-N divides the clock signal by n (n is an integer) and checks whether the clock signal is abnormal by checking whether the frequency of the divided clock signal is within a preset frequency range. can do.

5 is a diagram illustrating an abnormally confirmed clock signal.

As illustrated in FIG. 5 , it can be seen that the clock generation period generated during the device selection period T2 is abnormally increased compared to the clock of FIG. 4 . The slave device 120-N divides the frequency of the clock signal by n (n is an integer) and checks whether the frequency of the divided clock signal deviates from a preset frequency range, thereby generating an abnormal clock signal as shown in FIG. can be detected. The slave device 120 -N that has detected the abnormal clock signal may transmit a code indicating an error of the clock signal to the master device 110 through the MISO communication line. 5 exemplifies that an error code of '111' is generated in the MISO communication line.

6 is a flowchart illustrating a method of performing serial communication in a slave device according to another embodiment of the present invention.

Referring to FIG. 6 , the slave device 120 -N using the CS communication line 11 in common may receive a clock signal from the master device 110 through the CS communication line during the device selection period ( S101 ). . Subsequently, the slave device 120 -N may receive the operation target data from the master device 110 through the MOSI communication line ( S103 ). The slave device 120 -N may check the operation target data generated in the MOSI communication line based on the clock signal. In an embodiment, the slave device 120 -N may identify bits corresponding to the operation target data in the MOSI communication line based on the timing of the rising edge of the clock signal.

Next, the slave device 120 -N may obtain an operation result value by substituting a preset operation method for the operation target data ( S105 ). The operation method may include one or more logical operators and another data to be calculated together with the operation target data.

Next, the slave device 120 -N may check whether the operation result matches the information already held ( S107 ). The retained information may be identification information of the slave device 120 -N.

The slave device 120-N does not transmit a response to the master device 110 if the operation result value does not match the information already held, and then ignores the data received from the master device 110 through the MOSI. have. That is, the slave device 120 -N may not transmit a response to the master device 110 by determining that the communication target device is not itself, when the operation result value does not match the retained information.

On the other hand, the slave device 120-N may respond to the master device 110 using the MISO communication line when the operation result value matches the information already held (S109). The slave device 120 -N may transmit the operation result value to the master device 110 as the response.

Next, the slave device 120 -N may check the frequency of the clock signal received through the CS communication line during the device selection period ( S111 ). Next, the slave device 120 -N may check whether the clock signal is abnormal by checking whether the frequency of the clock signal is included in a preset frequency normal range ( S113 ). The slave device 120-N divides the clock signal by n (n is an integer) and checks whether the clock signal is abnormal by checking whether the frequency of the divided clock signal is within a preset frequency range. can do.

Next, when the frequency of the clock signal is within the normal range, the slave device 120 -N may communicate with the master device 110 ( S115 ). At this time, the slave device 120-N is synchronized with the master device 110 through the SPI clock received through the SCK communication line, and receives data from the master device 110 through the MOSI communication line, and MISO communication Data may be transmitted to the master device 110 through the line.

On the other hand, when the frequency of the clock signal deviates from the normal range, the slave device 120-N does not communicate with the master device 110 and transmits a code indicating an error of the clock signal to the master device through the MISO communication line. It can be transmitted to (110) (S117).

According to this embodiment, even if the slave device 120-N uses the CS communication line in common, it is precisely checked whether or not it is selected through the calculated result value, and communicates with the master device 110 without data collision. can be effective. In addition, according to this embodiment, by checking whether the clock signal received through the CS communication line is normal, it is possible to exhibit the advantage of verifying the failure of the master device.

The methods according to the embodiments of the present invention described so far may be performed by executing a computer program embodied as computer readable code. The computer program may be transmitted from the first computing device to the second computing device through a network such as the Internet and installed in the second computing device, thereby being used in the second computing device. The first computing device and the second computing device include all of a server device, a physical server belonging to a server pool for a cloud service, and a stationary computing device such as a desktop PC.

The computer program may be stored in a recording medium such as a DVD-ROM or a flash memory device.

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those of ordinary skill in the art to which the present invention pertains can realize that the present invention can be embodied in other specific forms without changing its technical spirit or essential features. can understand Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

Claims (12)

a plurality of slave devices for performing serial communication by forming a plurality of communication lines with the master device; and
A clock signal is transmitted to the plurality of slave devices through a CS (Chip Select) communication line commonly used by the plurality of slave devices, and operation target data for communication with any one of the plurality of slave devices is transmitted to a Master Output (MOSI). Slave Input) transmits to the plurality of slave devices through a communication line, identifies a slave device that responds based on a result value calculated using the clock signal and calculation target data as a communication target device, and identifies the identified slave comprising the master device communicating with the device;
The slave device checks whether the clock signal is abnormal by checking whether a frequency of the clock signal received through the CS communication line is included in a preset frequency range,
serial communication device. According to claim 1,
The slave device is
dividing the clock signal and checking whether the clock signal is abnormal by checking whether the divided clock signal is included in the preset frequency range;
serial communication device. According to claim 1,
The slave device is
When an abnormality of the clock signal is checked, a code indicating a clock error is transmitted to the master device through a MISO (Master Input Slave Output) communication line,
serial communication device. According to claim 1,
The slave device is
Computing the data to be calculated using a preset logical operator and communicating with the master device in response to the master device when the calculated result matches the retained information,
serial communication device. 5. The method of claim 4,
The slave device, when the calculated result value matches the identification information, transmits the calculated result value as the response to the master device through a MISO (Master Input Slave Output) communication line,
The master device checks whether the result value received from the MISO communication line is correct, and performs communication with the slave device if it is correct,
serial communication device. According to claim 1,
The master device is
Transmitting the operation target data corresponding to a predetermined bit to the plurality of slave devices,
serial communication device. According to claim 1,
The master device is
transmitting a clock signal to the plurality of slave devices and transmitting the operation target data to the plurality of slave devices during a device selection period for establishing communication;
serial communication device. A method for a slave device to perform serial communication with a master device, the method comprising:
Receiving a clock signal from the master device through a CS (Chip Select) communication line, and receiving operation target data from the master device through a MOSI (Master Output Slave Input) communication line;
obtaining operation target data received through the MOSI communication line based on the clock signal, and obtaining an operation result value based on the operation target data; and
Comprising the step of performing communication with the master device when the calculation result matches the information being stored in advance,
Serial communication method. 9. The method of claim 8,
The step of performing the communication comprises:
checking whether a frequency of the clock signal received through the CS communication line is included in a preset frequency range; and
When the frequency of the clock signal deviates from the preset frequency range, data received from the master device through the MOSI communication line is ignored, and a code indicating a clock error is transmitted through the MISO (Master Input Slave Output) communication line. sending to the master device;
Serial communication method. 10. The method of claim 9,
The step of checking whether it is included in the frequency range,
frequency-dividing the clock signal, comprising the step of checking whether the divided clock signal is included in the preset frequency range,
Serial communication method. 9. The method of claim 8,
The step of obtaining the result of the calculation includes:
calculating the operation target data using a preset logical operator; and
Comprising the step of transmitting a response signal for performing communication to the master device through a MISO (Master Input Slave Output) communication line when the calculated result value matches the retained information,
Serial communication method. 12. The method of claim 11,
Transmitting the response signal to the master device comprises:
Comprising the step of transmitting the calculated result value to the master device as the response signal,
Serial communication method.

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