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#include "defines.h"
#include <inttypes.h>
#include <util/delay.h>
#include "comm.h"
#include "usart.h"
static uint8_t comm_send_crc;
static unsigned int comm_send_length;
static unsigned int comm_send_pos;
static int comm_recv_pos;
static uint8_t comm_recv_crc;
static uint8_t comm_recv_error;
volatile uint8_t comm_recv_command;
volatile unsigned int comm_recv_length;
volatile uint8_t recv_buffer[RECV_BUFFER+8];
volatile uint8_t comm_recv_done;
static void comm_calc_send_crc(uint8_t inbyte)
{
uint8_t j;
for (j=0;j<8;j++)
{
uint8_t mix = (comm_send_crc ^ inbyte) & 0x01;
comm_send_crc >>= 1;
if (mix)
comm_send_crc ^= 0x8C;
inbyte >>= 1;
}
}
static void comm_calc_recv_crc(uint8_t inbyte)
{
uint8_t j;
for (j=0;j<8;j++)
{
uint8_t mix = (comm_recv_crc ^ inbyte) & 0x01;
comm_recv_crc >>= 1;
if (mix)
comm_recv_crc ^= 0x8C;
inbyte >>= 1;
}
}
static void comm_send_and_calc(uint8_t data)
{
comm_calc_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_calc_recv_crc(data);
unsigned int l = comm_recv_pos-4;
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:
if (l >= sizeof(recv_buffer))
{
comm_recv_pos = 0;
comm_recv_error = 1;
comm_start(COMMAND_ERROR_OVERFLOW, 0);
return;
}
else if (l < comm_recv_length)
{
recv_buffer[l] = data;
} else if (l == 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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