KR20050069345A - Micro-computer and rs-232c transmitting/receiving method the same - Google Patents

Abstract

MICOM and RS-232C transmitting / receiving method which enables RS-232C processing by internal configuration only without separate RS-232C processing device, and GPIO (general purpose input / output) connected to one of the terminals with Tx B), an interrupt handler with a receiving terminal (Rx) connected to one of the terminals, and a GPIO terminal state (high / low) control with a transmitting terminal (Tx) and a baud rate promised between the sender / receiver for each state control step. Transmit according to RS-232C protocol through delay insertion according to the protocol, and read interrupt handler terminal status (high / low) connected to receiver Rx by referring to delay time inserted according to the baud rate promised between transmitter / receiver. Including the CPU to perform the reception according to the RS-232C protocol can increase the utilization of the microcomputer, and can be applied to each electronic product that requires the RS-232C function can lower the product price.

Description

MICOM and its RS-232C Transmitting / Receiving Method {Micro-Computer and RS-232C Transmitting / Receiving Method the Same}

The present invention relates to a micro-computer (Micro-Computer, hereinafter referred to as a microcomputer) and RS-232C transmitting / receiving method for enabling RS-232C processing by only an internal configuration without a separate RS-232C processing apparatus.

RS-232C, one of the representative asynchronous communication protocols, has recently been used in home appliances such as TVs.

Its purpose is to enable the TV microcomputer programmer to send a message to the host by inserting a print statement between the programs in order to check step by step whether the program works properly. ) For use in case of controlling by TV, not by remote control to control several TVs individually in industrial TV such as home theater or hotel, and for recent communication between home appliances in home network, in factory This is to use for automatic video adjustment and program download during TV production.

Therefore, recently commercial microcomputers have built-in RS-232C in hardware, but most of the microcomputers currently being developed do not have the RS-232C block.

That is, as shown in Figure 1, the conventional microcomputer 10 without the RS-232C block is a CPU 11, GPIO (General Purpose Input / Output) 12 for the operation and communication control of the product, It comprises a general purpose input / output device, an interrupt handler 13 for performing an interrupt routine, and a peripheral device 14.

However, as the demand for RS-232C response is increasing in the market, a solution is required.

In particular, in the case of digital TV, since the main microcomputer is an expensive multifunction chip, the RS-232C block is built in, but the submicrocom for standby control is still inexpensive.

Therefore, the microcomputer according to the related art does not have an RS-232C block, and thus communication with the RS-232C is impossible.

Accordingly, the present invention has been made to solve the above-described problems, and provides a microcomputer and RS-232C transmission / reception method thereof capable of RS-232C processing using only an internal configuration without a separate RS-232C processing apparatus. There is a purpose.

According to the present invention, a microcomputer has a GPIO (general purpose input / output) connected to one of the terminals (Tx), an interrupt handler connected to one of the terminals (Rx), and a GPIO terminal connected to the transmitter (Tx). Transmit according to RS-232C protocol through (high / low) control and delay insertion according to the baud-rate promised between senders and receivers in each status control, and insert according to the promised baud rates between senders and receivers And a CPU that reads the interrupt handler terminal state (high / low) to which the receiving end Rx is connected with reference to the delay time, and performs reception according to the RS-232C protocol.

The RS-232C transmission / reception method of the microcomputer according to the present invention controls the state (high / low) of the GPIO terminal to which the transmitter Tx is connected, generates a start bit, and transmits the baud rate to the transmitter / receiver. Performing transmission by delaying according to the delay, repeating the delay according to the baud rate of the GPIO terminal state connected to the transmitter end Tx after the start bit transmission and each state control step, and performing data generation and transmission of a predetermined bit. And controlling the state of the GPIO terminal to which the transmitter Tx is connected after transmission, generating a stop bit, and delaying it according to the baud rate to complete the transmission.

Hereinafter, a preferred embodiment of the microcomputer and its RS-232C transmission / reception method according to the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 is a block diagram showing the configuration of a microcomputer according to the present invention, Figure 3 is a signal waveform according to the RS-232C protocol, Figure 4 is a flow chart showing a RS-232C transmission method of the microcomputer according to the present invention, 5 is a flowchart illustrating a method of receiving a microcomputer RS-232C according to the present invention.

As shown in FIG. 2, the microcomputer according to the present invention has a GPIO 22 having a transmitting end Tx connected to one of the terminals, an interrupt handler 23 having a receiving end Rx connected to one of the terminals, and the transmitting end. It performs transmission according to RS-232C protocol through GPIO 22 terminal status (high / low) control connected with (Tx) and delay insertion according to the baud-rate promised between senders and receivers in each status control step. CPU that reads the state of the interrupt handler 23 terminal (high / low) to which the receiving end Rx is connected with reference to the delay time inserted according to the baud rate promised between the sender / receiver and performs reception according to the RS-232C protocol. It comprises 21.

The RS-232C transmission / reception method of the microcomputer according to the present invention configured as described above will be described in detail.

First, prior to the description of the present invention, looking at the signal format according to the RS-232C protocol, as shown in Figure 3, the start bit (low level), the data (for example, 1 byte: 8 bit), and the stop bit (high) Level).

-How to send microcomputer RS-232C-

The RS-232C transmission method of the microcomputer according to the present invention will be described with reference to FIG. 4 as follows.

First, since the transmitting terminal Tx of the microcomputer 20 is connected to the GPIO 22, the CPU 21 makes the state of the port of the GPIO 22, that is, the port connected to the transmitting terminal Tx, 'low' ( S41).

At this time, the CPU 21 can control the GPIO 22 port direction (output / input) related register first to set the GPIO 22 port direction, and control the GPIO 22 port value related register to control the state of the port. It can be made 'high' or 'low'.

Therefore, the CPU 21 controls the register related to the GPIO 22 port direction (output / input) for transmission to set the GPIO 22 port direction as the output, and the GPIO 22 to generate the start bit of FIG. Controls port-related registers to make the port state low.

The CPU 21 delays the port state in order to match a baud rate set in advance between the transmitter and the receiver (S42).

In this case, the delay operation is performed by the CPU 21 rotating a predetermined dummy loop without proceeding to the next.

Next, the CPU 21 checks each bit value of the byte to be transmitted (S43), and determines whether the first data bit to be transmitted is 'high' (S44).

As a result of the determination (S44), if the state is 'high', the GPIO 22 port state is made high, and the bit count value is increased (S45), and a delay operation for adjusting the baud rate is performed (S47).

On the other hand, if the determination result (S44) is not 'high', that is, 'low', the GPIO 22 port state is made low, and the bit count value is increased (S46). The operation is performed (S47).

Then, it is determined whether the bit count value is '8 (1 byte)' (S48), and if the value is not '8', the steps S44 to S47 are repeated.

On the other hand, if the bit count value is '8', the determination result (S48) controls the register related to the GPIO 22 port value to generate the stop bit of FIG. 3 to make the port state 'high' (S49).

Subsequently, a delay operation for adjusting the baud rate is performed (S50), so that one-byte data transmission according to the RS-232C protocol is completed.

-How to receive RS-232C from Microcomputer-

RS-232C receiving method of the microcomputer according to the present invention will be described with reference to FIG.

The receiving end Rx of the microcomputer 20 is connected to the interrupt handler 23.

Therefore, in the case of reception, the interrupt related register is controlled to set the CPU 21 program to jump to the interrupt handler routine in the edge state of the receiving end Rx.

In this case, the edge state means that the receiving end Rx is toggled from 'high' to 'low' so that a start bit is input.

Therefore, at the same time as entering the interrupt handler routine, the operation of delaying the reception, that is, reading the data, is delayed until the data bit is input (S51).

Subsequently, after the delay operation (S51), the port state (high / low) of the interrupt handler 23 is read (S52).

In operation S53, the read port state is determined to be 'high', and if the port state is 'high', the port is recognized as '1' and the bit count value is increased (S54). (S56).

On the other hand, the determination result (S53), if the port state is 'low' is recognized as '0' and after increasing the bit count value (S55), and performs a delay operation for adjusting the baud rate (S56).

Then, it is determined whether the bit count value is '8 (1 byte)' (S57), and if the value is not '8', the steps S52 to S56 are repeated.

On the other hand, if the bit count value is '8' in the determination result (S57), the read one-byte data processing operation, that is, storing is performed (S58), completes the data receiving operation and exits from the interrupt handler routine.

The microcomputer and its RS-232C transmission / reception method according to the present invention are capable of RS-232C communication even in the case of a microcomputer that does not have a separate RS-232C hardware block.

Therefore, it is possible to increase the utilization of the microcomputer and to apply to each electronic product requiring the RS-232C function, thereby reducing the product price.

1 is a block diagram showing the configuration of a microcomputer according to the prior art

2 is a block diagram showing the configuration of a microcomputer according to the present invention;

3 is a diagram illustrating a signal waveform according to the RS-232C protocol.

4 is a flowchart showing a method of transmitting a microcomputer RS-232C according to the present invention.

5 is a flowchart showing a method of receiving a microcomputer RS-232C according to the present invention.

-Explanation of symbols for the main parts of the drawings-

20: Micom 21: CPU

22: GPIO 23: interrupt handler

24: Peripherals

Claims (5)

A GPIO (general purpose input / output unit) to which a transmission terminal Tx is connected to any one of terminals; An interrupt handler having a receiving end Rx connected to any one of terminals; And It performs transmission according to the RS-232C protocol by inserting a delay according to the baud rate promised between the transmitter / receiver for each state control step and the GPIO terminal state (high / low) to which the transmitter Tx is connected, A microcomputer including a CPU that reads the interrupt handler terminal state (high / low) to which the receiving end Rx is connected and performs reception according to the RS-232C protocol by referring to the delay time inserted according to the baud rate promised between the transmitter and the receiver. . In the microcomputer RS-232C transmission method having a GPIO (general purpose input / output) and a CPU connected to one of the terminals (Tx), Controlling a GPIO terminal state (high / low) to which the transmitting end (Tx) is connected, generating a start bit and delaying it according to the baud rate promised between the sender / receiver to perform transmission; Performing data generation and transmission of a predetermined bit by repeating the GPIO terminal state control to which the transmitter Tx is connected and the delay according to the baud rate for each state control step after transmitting the start bit; And And controlling the state of the GPIO terminal to which the transmitting terminal (Tx) is connected after the data transmission, generating a stop bit, and delaying according to the baud rate to complete the transmission. The method of claim 2, The GPIO terminal state (high / low) control is a microcomputer RS-232C transmission method characterized in that the CPU is controlled by controlling the register of the port value of the GPIO. The method of claim 2, The delay according to the baud rate is a microcomputer RS-232C transmission method, characterized in that is made by rotating the dummy loop without proceeding to the next operation. In the method of receiving a microcomputer RS-232C having an interrupt handler and a CPU connected to one of the terminals (Rx), Entering an interrupt handler routine according to an interrupt handler terminal state (high / low) to which the receiving end Rx is connected; Performing a delay operation according to a baud rate promised between a transmitter and a receiver when a start bit is input; And After the delay operation is performed, the process of reading the interrupt handler terminal state connected to the receiving terminal Rx as data bits and repeating the delay operation according to the baud rate until all data bits are read is completed. RS-232C reception method of the microcomputer included.