int8_t _bmac_tx()
{
uint8_t v,backoff, backoff_count;
uint16_t b;
#ifdef DEBUG
nrk_kprintf( PSTR("_bmac_tx()\r\n"));
#endif
if(cca_active)
{
// Add random time here to stop nodes from synchronizing with eachother
b=_nrk_time_to_ticks(&_bmac_check_period);
b=b/((rand()%10)+1);
//printf( "waiting %d\r\n",b );
nrk_wait_until_ticks(b);
//nrk_wait_ticks(b);
backoff_count=1;
do{
v=_bmac_channel_check();
rf_rx_off();
if(v==1) break;
// Channel is busy
backoff=rand()%(_b_pow(backoff_count));
#ifdef DEBUG
printf( "backoff %d\r\n",backoff );
#endif
// printf( "backoff %d\r\n",backoff );
nrk_wait_until_next_n_periods(backoff);
backoff_count++;
if(backoff_count>6) backoff_count=6; // cap it at 64
b=_nrk_time_to_ticks(&_bmac_check_period);
b=b/((rand()%10)+1);
// printf( "waiting %d\r\n",b );
nrk_wait_until_ticks(b);
// nrk_wait_ticks(b);
} while(v==0);
}
rf_test_mode();
rf_carrier_on();
nrk_wait(_bmac_check_period);
//nrk_wait_until_next_period();
rf_carrier_off();
rf_data_mode();
// send packet
rf_rx_off();
pkt_got_ack=rf_tx_packet (&bmac_rfTxInfo);
rf_rx_off();
tx_data_ready=0;
nrk_event_signal (bmac_tx_pkt_done_signal);
return NRK_OK;
}
int8_t _bmac_tx()
{
uint8_t v,result, backoff, backoff_count;
uint16_t b;
if(cca_active) {
// Add random time here to stop nodes from synchronizing with eachother
b=_nrk_time_to_ticks(&_bmac_check_period);
b=b/((rand()%10)+1);
//printf( "waiting %d\r\n",b );
nrk_wait_until_ticks(b);
//nrk_wait_ticks(b);
backoff_count=1;
do
{
v=_bmac_channel_check();
rf_rx_off();
if(v==1) break;
// Channel is busy
backoff=rand()%(_b_pow(backoff_count));
// printf( "backoff %d\r\n",backoff );
nrk_wait_until_next_n_periods(backoff);
backoff_count++;
if(backoff_count>6) backoff_count=6; // cap it at 64
b=_nrk_time_to_ticks(&_bmac_check_period);
b=b/((rand()%10)+1);
// printf( "waiting %d\r\n",b );
nrk_wait_until_ticks(b);
// nrk_wait_ticks(b);
}
while(v==0);
}
// Give check_period worth of channel activity
rf_test_mode();
rf_carrier_on();
nrk_wait(_bmac_check_period);
rf_carrier_off();
rf_data_mode();
rf_rx_off();
pkt_got_ack = rf_tx_packet(&bmac_rfTxInfo);
rf_rx_off();
tx_data_ready = 0;
// Should signal user task here that Tx is done
return NRK_OK;
}
