uart-command-parser

Concerning debugging in the embedded application, a common method is to change the input value by pressing the button.

Generally, a button has two available states: pressed and unpressed, which means we can provide only two different input for testing. But in many cases, I would like to input as many values as I want in the testing. That's why I make this project.

With this project, actually it's a pair of .c and .h files, user types the command in UART terminal and firmware executes the corresponding handler.

Usage

The basic usage is:

@ command_string = command_parameter \n

'@' is the prefix of a command.

command_string is user defined and its length should be less than 5 bytes.

command_parameter will be passed to user defined handler. And the total length of input string should be less than 64 bytes.

The total string ends with a new line sign '\n'(0x0A).

A string without @ prefix will be parsed as a Message. Message will be printed out immediately in current project. (If we route the message to BLE notification interface, it is BLE-UART passthrough.)

Example

I prepare three sets of command in the applicaiton code:

• {"APP1", appHandler1}
• {"APP2", appHandler2}
• {"APP3", appHandler3}

And register these handlers to the handler table:

#include "ucmd.h"

void app_handler1(uint8* data, uint8 len)
{
    ucmd_print("Command: name=%s, param=", "APP1");
    if (len == 0) {
        ucmd_print("NULL");   
    }
    else {
        uint8 i;
        for (i = 0; i < len; i++) {
            ucmd_print("%c", data[i]);   
        }
    }
    ucmd_print("\r\n");
}

void app_handler2(uint8* data, uint8 len){;}
void app_handler3(uint8* data, uint8 len){;}

ucmd_registerHandler("APP1", app_handler1);
ucmd_registerHandler("APP2", app_handler2);
ucmd_registerHandler("APP3", app_handler3);

In the UART terminal, type @APP1=123456\n, then appHandler1 will be invoked with parameter "123456", as shown in the following figure:

If typing a stirng without @ prefix, the terminal will print the echo string:

Work Flow

UART is the core of this system. It monitors the input byte stream continousely and save bytes in a buffer. Once finding a tail tag('\n'), parse and process it.

• Uart Monitor: It's the UART RX interrupt.
• Parser cmd: Once it find a command, push it to a task queue. So it has potential to process multiple tasks.
• Run cmd: user can register arbitrary quantity of command by hand.

Note

This project is half-complete. It should work basically, however, I don't do many tests on it.

Unfortunately, I don't have time(or chance) to improve it anymore. :-(

I think it's still helpful if someone has a heavy debugging task or wants to implement a BLE-UART passthrough project.

(End)