Motor-Controller/shared/drivers/p_serial_mgr.c

#include "p_serial_mgr.h"
#include "putil.h"
#include "stm32l4xx_hal_uart.h"

#define MAX_SERIAL_BUFFER_SIZE (262) // Actually 261, add 1 for padding

// this protocol is very similar to the digi api v2 (inspired from)
// [0]{1} Start delimiter 0x7E
// [1]{1} Source Address
// [2]{1} Destination Address
// [3]{1} Length Byte (of non-delimited framebuffer)
// [4-n]{n} frame data
// [n+1]{1} checksum
// Escape bytes are 0x7D, only frame data can be escaped
// Escaped bytes are followed by the byte to be escaped XOR'd with 0x20
// 0x7D and 0x7E need to be escaped (within the frame data)

typedef enum serial_state_t
{
	SS_IDLE = 0,  // waiting
	SS_START = 1, // get start byte, interrupt after 4 more bytes
} serial_state_t;

static UART_HandleTypeDef *_serial_huart_inst = NULL;

static uint8_t rxc = '\0';
static serial_state_t sstate = SS_IDLE;

void UART1_RxCpltCallback(UART_HandleTypeDef *huart)
{
	if (rxc == 0x7E && sstate == SS_IDLE)
	{
		sstate = SS_START;
	}
}

void p_serial_mgr_init(UART_HandleTypeDef *huart)
{
	_serial_huart_inst = huart;
	_serial_huart_inst->RxCpltCallback = UART1_RxCpltCallback;
}
void p_serial_mgr_service(void)
{
	if (sstate == SS_START)
	{
		return;
	}
	else if (sstate = SS_IDLE) {}
	return b_go;
}

void p_serial_mgr_start()
{
	b_go = false;
	HAL_UART_Receive_IT(_serial_huart_inst, &rxc, 1);
}