uint8_t sja1000_get_message(can_t *msg)
{
uint8_t frame_info;
uint8_t address;
// check if there is actually a message in the buffers
if (!sja1000_check_message())
return FALSE;
frame_info = sja1000_read(16);
msg->length = frame_info & 0x0f;
if (frame_info & (1<<FF))
{
// read extended identifier
msg->flags.extended = 1;
uint32_t tmp;
uint8_t *ptr = (uint8_t *) &tmp;
*ptr = sja1000_read(20);
*(ptr + 1) = sja1000_read(19);
*(ptr + 2) = sja1000_read(18);
*(ptr + 3) = sja1000_read(17);
msg->id = tmp >> 3;
/* equivalent to:
msg->id = sja1000_read(20) >> 3;
msg->id |= (uint16_t) sja1000_read(19) << 5;
msg->id |= (uint32_t) sja1000_read(18) << 13;
msg->id |= (uint32_t) sja1000_read(17) << 21;*/
address = 21;
}
can_error_register_t sja1000_read_error_register(void)
{
can_error_register_t error;
error.tx = sja1000_read(TXERR);
error.rx = sja1000_read(RXERR);
return error;
}
// ----------------------------------------------------------------------------
void sja1000_reset_bus_off(void)
{
uint8_t status = sja1000_read(SR) & (1<<BS);
sja1000_write(SR, status & ~(1<<BS));
}
bool sja1000_check_bus_off(void)
{
return (sja1000_read(SR) & (1<<BS));
}
