KR100567033B1 - Method for operating synchronous serial communication in which master and slave are fixed - Google Patents

Abstract

In a system where device-to-device communication is very important, in order to improve the communication speed and improve the stability of the communication system, the master and the slave communicate simultaneously at predetermined intervals according to the clock signal generated from the master. In addition to the command message (C _n ) for controlling the slave, the data including the communication response confirmation for the result message (R _n-2 ) transmitted from the slave in the previous period (n-1) is transmitted to the slave, and the slave Is a result message (R _n-) containing the result obtained by performing the command message (C _n-1 ) with acknowledgment of the communication response to the command message (C _n-1 ) sent from the master in the previous period (n-1). ₁ ) A synchronous serial communication method in which a master and a slave are fixed is provided.

Synchronous serial communication, master, slave

Description

Synchronous serial communication with fixed master and slave {METHOD FOR OPERATING SYNCHRONOUS SERIAL COMMUNICATION IN WHICH MASTER AND SLAVE ARE FIXED}

1 is a process flow diagram of data transmission according to a prior art serial communication method.

2 illustrates a synchronous serial communication format in bytes according to the present invention.

3 illustrates a synchronous serial communication format on a packet basis according to the present invention.

4 is a process flow diagram of data transmission in accordance with the present invention;

5 is a data structure of a slave side in data transmission according to the present invention.

* Description of the symbols for the main parts of the drawings *

CS #: Chip Select CLK: Clock Signal

MOSI: Master Output / Slave Input MISO: Master Input / Slave Output

Cn: command message N: null message

Rn: result message

The present invention relates to a synchronous serial communication method in which a master and a slave are fixed, and more particularly, in communication between an ATSC receiving module (hereinafter referred to as a 'decoder module') and a TV SET microcomputer (hereinafter referred to as a 'microcom'). The present invention relates to a simultaneous serial communication method in which a master and a slave are fixed.

As the processing speed of digital devices, ICs, and processors increases, the speed and performance of the entire system are improving. Due to the characteristics of the system, systems in which communication between devices is important are faced with the demand for higher communication speed.

There are two types of serial communication, synchronous serial communication and asynchronous serial communication. In the case of synchronous communication, synchronization is performed between two devices, data is transmitted and received according to the timing, and a control signal flows even when there is no data exchange, so that it is possible to maintain synchronization with the other party. When real data is transmitted, it is received. When there is no data, a signal indicating a waiting state is exchanged. When communication is established in this manner, the data transfer speed is increased because no signal indicating the start and end of data exists in the transmission and reception of real data.

For asynchronous communication, there is no need for send and receive idle characters. However, at the beginning and end of the data, there is a start bit and a stop bit. The start bit indicates the start of data and the stop bit indicates the end of data. Thus, the addition of these two bits slows the speed of asynchronous communication slightly compared to synchronous communication.

As described above, such a communication speed contributes greatly to the performance of the system, thereby increasing the demand for a synchronous communication method rather than an asynchronous communication method in serial communication.

Referring to FIG. 1, the processing flow of data transmission according to the conventional serial communication method is as follows.

When the master (e.g., the decoder module) sends a communication command (C1) to the slave (e.g., TV SET (microcomm)), the decoder module soon switches to the slave mode. It is necessary. When the microcomputer receives the communication command C1 in the slave mode, the microcomputer switches the communication state from the slave mode to the master mode.

The microcomputer should transmit a communication response acknowledgment (ACK1-C1) within the preset timeout period of the decoder module. If the decoder module does not receive an ACK within the preset timeout period, the decoder module should switch to the retransmission mode.

The microcomputer sending the communication response acknowledgment (ACK1-C1) performs the command and transmits the result value R1, and then switches the communication back to the slave mode. The microcomputer switches to the slave mode in this way, and prepares to receive the communication response confirmation (ACK1-R1) regarding whether the decoder module has properly received the result value R1, and the decoder module switches to the master to confirm the communication response (ACK1). -R1). If communication for this also does not occur within a predetermined timeout period, the microcomputer retransmits the result of executing the command.

As described above, aperiodic synchronization between the master and the slave, such as confirming the command from the master to the slave, confirming the communication response from the slave to the master and transmitting the result of the command, confirming the communication response from the master to the slave, etc. According to the serial communication, communication switching time between the master and the slave is always required, and when the communication response is not acknowledged, a time interval for determining the communication error processing must be set, so communication efficiency becomes very poor, and system performance is very degraded. do.

In addition, if the slave is relatively slower than the master, the communication speed becomes slower in the system where the master and slave communication is the main, resulting in lowering the overall performance of the system. This makes it difficult to test processing for communication errors.

The present invention is to overcome the above-mentioned problems, the object of the present invention is to improve the performance of the system by improving the communication speed, the stability of the communication in a system where the communication between devices is very important, It is to provide a fixed periodic synchronous serial communication method.

According to an aspect of the present invention for achieving the object of the present invention, in the synchronous serial communication method in which the master and slave is fixed so that the master and slave communication at the same time every predetermined period in accordance with the clock signal generated from the master The master includes data including a communication response confirmation for the result message R _n-2 transmitted from the slave in a previous period n-1 together with a command message C _n for controlling the slave. At the same time, the slave obtains a communication response to the command message (C _n-1 ) transmitted from the master in the previous period ( _n-1 ) and performs the command message (C _n-1 ). And transmitting data including a result message (R _n-1 ) including a result value.

Data transmitted from the master to the slave is transmitted from the master to the slave in the form of a header for distinguishing the data group, a command message, confirming the communication response to the previous period and the checksum of the data group of the current period. do.

The data transmitted from the slave to the master includes a header for identifying the data group, a result message, a confirmation of the communication response for the previous period, a checksum of the data group of the current period, and a validity of the data transmitted by the slave. It is characterized by being transmitted from the slave to the master in the form of a (validity).

The data transmitted between the master and the slave may be transmitted in frame or packet units.

The master is a decoder module, and the slave is a TV SET microcomputer.

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

Referring to FIG. 2, a diagram illustrating a synchronous serial communication format in byte units according to the present invention will be described.

Serial Peripheral Interface (SPI) communication is a full-duplex synchronous serial interface that connects to a peripheral device. Communication is through four lines. Each line is Chip Select (CS #), Clock (CLK), Master Output / Slave Input (MOSI) and Master Input / Slave Output (MISO). Chip Select and Clock are Control Lines. MOSI and MISO are Data Lines. to be.

As shown in FIG. 2, when the master enables the chip select (CS #) pin, a clock is generated in the master (decoder module in this embodiment). According to the clock generated in the master, data is simultaneously transmitted from the master to the slave (TV SET micom in this embodiment) and from the slave to the master via MOSI and MISO.

FIG. 3 is a diagram illustrating a synchronous serial communication format in a packet unit according to the present invention. FIG. 3 is a diagram illustrating how one packet is configured, and the rest is the same as that of FIG.

To send one packet, the decoder module enables the chip select (CS #) pin (LOW) and generates a clock for multiple bytes. In accordance with the clock generation, the command byte is transmitted from the decoder module to the TV SET microcomputer, and at the same time, the data is transmitted from the TV SET microcomputer to the decoder module. The number of bytes, data transmission time, etc. that constitute one packet shown in FIG. 3 are merely examples.

Referring to Figure 4, the flow of data transmission processing according to the present invention will be described. When the decoder module is assumed to be a master and the TV SET micom is a slave, the decoder module operates as a master, so that the decoder module periodically communicates with the TV SET micom every predetermined period (for example, 100 ms) to know the state of the TV SET.

The decoder module sends a command message if necessary and a NULL message if there is no message to send. Here, the command message refers to data sent by the decoder module to control the TV SET microcomputer.

When the TV SET micom communicates, it basically sends a status message indicating the TV SET status to the decoder module, and when a result value obtained by performing a command message received from the decoder module occurs, the TV SET micom transmits a result message instead of a status message. Done. Here, the status message includes a TV SET status, that is, a remote controller, a front key value, and an external input status, and means data that is always transmitted even without a command from the decoder module, and the result message is a command received from the decoder module. Means the result obtained. Therefore, the result message cannot be transmitted until the command message is received from the decoder module.

When the decoder module transmits the first command message C1 to the microcomputer, the microcomputer cannot transmit the communication response acknowledgment until the current computer receives the current command. Therefore, the command message C1 is transmitted from the decoder module to the micom, and the null message N is transmitted from the decoder module to the decoder module.

Then, the decoder module sends a command message C2 to the microcomputer, and the microcomputer transmits a result message R1 including the confirmation of the communication response to the previous command message C1 and the result value obtained by performing the C1. Done.

Then, the decoder module sends a command message C3 including the communication response confirmation to the result message R1 to the microcomputer, and at the same time, the microcomputer sends the communication response confirmation to the previous command message C2 and the C2. The result message R2 including the result value obtained by the execution is transmitted.

As such, the decoder module sends a communication response acknowledgment for the result message sent from the microcomputer at the next command message (or null message) transmission, and the microcomputer transmits a communication response acknowledgment for the command message received from the decoder module and the command. The result of the message is transmitted when the next command message (or null message) is received from the decoder module. As a result, communication switching time is not required, and communication efficiency is greatly improved.

5 is a data structure of a slave side in data transmission according to the present invention. As shown in FIG. 4, when the master (decoder module) and the slave (microcom) are fixed and communicate data at the same time, the situation of the slave may not be known when the communication will occur. That is, when the master sends a clock, the slave needs to send data through the MISO according to the clock signal, so it is necessary to send the validity of the data sent by the slave.

To this end, the data structure sent from the slave side to the master includes a header that distinguishes the data group, a validity that indicates the validity of each byte sent, and a communication response confirmation for confirming a response to the previous communication. (Ack) and the checksum (CS) of the current data group. In this case, the validity means that the result value of each byte is a valid value, and thus it is possible to know whether to process the data effectively when receiving and processing data from the master side.

The validity B0-B7 shown in FIG. 5 shows the data validity from data 1-data 8. For example, if B7 is 1, data 1 is valid. If B7 is 0, it means that it is invalid.

On the other hand, the data structure of the master side consists of a header without validity, a communication response confirmation, and a checksum of the current data group.

What has been described above is only an exemplary embodiment of a synchronous serial communication method in which a master and a slave are fixed according to the present invention, and the present invention is not limited to the above-described embodiment, and as claimed in the following claims, Without departing from the gist of the present invention, anyone of ordinary skill in the art will have the technical spirit of the present invention to the extent that various modifications can be made.

As described above, according to the fixed synchronous serial communication method of the master and the slave of the present invention, the master / slave (main / slave) of the communication is fixed and switching time is reduced, and the validity of the communication is the communication of the next cycle. When the checksum results are sent, the response confirmation saves additional traffic.

In addition, since the master is very fast, periodic communication is not burdened. Slave is the result transmission after executing the command by the communication. Therefore, even if there is a lot of work assignment for communication, it is not a burden. Less program memory is required for processing and testing is easier.

Claims (5)

In the synchronous serial communication method in which the master and the slave is fixed so that the master and the slave communicates at the same time every predetermined period in accordance with the clock signal generated from the master, The master transmits data including acknowledgment of communication response to the result message (R _n-2 ) transmitted from the slave in the previous period (n-1) together with a command message (C _n ) for controlling the slave to the slave. Simultaneously with the transmission, a result obtained by performing the command message (C _n-1 ) together with acknowledgment of the communication response to the command message (C _n-1 ) transmitted from the master in the previous period (n-1) A fixed synchronous serial communication method in which a master and a slave are transmitted with data including a result message R _n-1 including a value. The data transmitted from the master to the slave comprises a header for distinguishing a data group, a command message, a communication response confirmation for a previous period, and a checksum of a data group of a current period. A synchronous serial communication method in which a master and a slave are fixed to the slave. The data of claim 1, wherein the data transmitted from the slave to the master includes a header for identifying a data group, a result message, a communication response confirmation for a previous period, a checksum of a data group of a current period, and the slave. A fixed serial communication method of a master and a slave, wherein the master and the slave are transmitted from the slave to the master in a form of validity indicating the validity of the data. The method according to any one of claims 1 to 3, wherein the data transmitted between the master and the slave is transmitted in a frame or packet unit. 5. The method of claim 4, wherein the master is a decoder module and the slave is a TV SET microcomputer.

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