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#include "defines.h"
#include <inttypes.h>
#include <util/delay.h>
#include "comm.h"
#include "usart.h"
#include "crc.h"
static uint8_t comm_send_crc; // CRC of outgoing packet with header
static uint16_t comm_send_length; // size of outgoing data
static uint16_t comm_send_pos; // how many data sent by app
volatile uint8_t recv_buffer[RECV_BUFFER_SIZE];
static uint16_t comm_recv_pos; // how many bytes of packet received
static uint8_t comm_recv_crc;
static uint8_t comm_recv_error;
volatile uint8_t comm_recv_command;
volatile uint16_t comm_recv_length;
volatile uint8_t comm_recv_done;
static void comm_send_and_calc(uint8_t data)
{
comm_send_crc = calc_crc8(comm_send_crc, data);
USART_TransmitByte(data);
#ifdef SEND_DELAY
_delay_us(SEND_DELAY);
#endif
}
void comm_start(uint8_t command, unsigned int length)
{
comm_send_crc = 0;
comm_send_and_calc('F');
comm_send_and_calc(command);
comm_send_and_calc(length & 0xff);
comm_send_and_calc((length >> 8) & 0xff);
comm_send_length = length;
comm_send_pos = 0;
if (!comm_send_length)
USART_TransmitByte(comm_send_crc);
}
void comm_send_byte(uint8_t data)
{
comm_send_and_calc(data);
comm_send_pos++;
if (comm_send_pos == comm_send_length)
USART_TransmitByte(comm_send_crc);
}
void comm_proceed(uint8_t data)
{
if (comm_recv_error && data != 'F')
return;
comm_recv_error = 0;
if (!comm_recv_pos)
{
comm_recv_crc = 0;
comm_recv_done = 0;
}
comm_recv_crc = calc_crc8(comm_recv_crc, data);
switch (comm_recv_pos)
{
case 0:
{
if (data != 'F')
{
comm_recv_error = 1;
comm_start(COMMAND_ERROR_INVALID, 0);
}
}
break;
case 1:
{
comm_recv_command = data;
}
break;
case 2:
{
comm_recv_length = data;
}
break;
case 3:
{
comm_recv_length |= (uint16_t) data << 8;
}
break;
default:
{
uint16_t pos = comm_recv_pos - 4;
if (pos >= sizeof(recv_buffer))
{
comm_recv_pos = 0;
comm_recv_error = 1;
comm_start(COMMAND_ERROR_OVERFLOW, 0);
return;
} else if (pos < comm_recv_length)
{
recv_buffer[pos] = data;
} else if (pos == comm_recv_length)
{
if (!comm_recv_crc)
{
comm_recv_done = 1;
} else
{
comm_recv_error = 1;
comm_start(COMMAND_ERROR_CRC, 0);
}
comm_recv_pos = 0;
return;
}
}
break;
}
comm_recv_pos++;
}
void comm_init()
{
comm_recv_pos = 0;
comm_recv_done = 0;
comm_recv_error = 0;
}
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