int sam_freerun_initialize(struct sam_freerun_s *freerun, int chan,
uint16_t resolution)
{
uint32_t frequency;
uint32_t divisor;
uint32_t cmr;
int ret;
tmrinfo("chan=%d resolution=%d usec\n", chan, resolution);
DEBUGASSERT(freerun && resolution > 0);
/* Get the TC frequency the corresponds to the requested resolution */
frequency = USEC_PER_SEC / (uint32_t)resolution;
/* The pre-calculate values to use when we start the timer */
ret = sam_tc_divisor(frequency, &divisor, &cmr);
if (ret < 0)
{
tmrerr("ERROR: sam_tc_divisor failed: %d\n", ret);
return ret;
}
tmrinfo("frequency=%lu, divisor=%u, cmr=%08lx\n",
(unsigned long)frequency, (unsigned long)divisor,
(unsigned long)cmr);
/* Allocate the timer/counter and select its mode of operation
*
* CMR_TCCLKS - Returned by sam_tc_divisor
* TC_CMR_CLKI=0 - Not inverted
* TC_CMR_BURST_NONE - Not gated by an external signal
* TC_CMR_CPCSTOP=0 - Don't stop the clock on an RC compare event
* TC_CMR_CPCDIS=0 - Don't disable the clock on an RC compare event
* TC_CMR_EEVTEDG_NONE - No external events (and, hence, no edges
* TC_CMR_EEVT_TIOB - ???? REVISIT
* TC_CMR_ENET=0 - External event trigger disabled
* TC_CMR_WAVSEL_UP - TC_CV is incremented from 0 to 0xffffffff
* TC_CMR_WAVE - Waveform mode
* TC_CMR_ACPA_NONE - RA compare has no effect on TIOA
* TC_CMR_ACPC_NONE - RC compare has no effect on TIOA
* TC_CMR_AEEVT_NONE - No external event effect on TIOA
* TC_CMR_ASWTRG_NONE - No software trigger effect on TIOA
* TC_CMR_BCPB_NONE - RB compare has no effect on TIOB
* TC_CMR_BCPC_NONE - RC compare has no effect on TIOB
* TC_CMR_BEEVT_NONE - No external event effect on TIOB
* TC_CMR_BSWTRG_NONE - No software trigger effect on TIOB
*/
cmr |= (TC_CMR_BURST_NOTGATED | TC_CMR_EEVTEDG_NONE | TC_CMR_EEVT_TIOB |
TC_CMR_WAVSEL_UP | TC_CMR_WAVE | TC_CMR_ACPA_NONE |
TC_CMR_ACPC_NONE | TC_CMR_AEEVT_NONE | TC_CMR_ASWTRG_NONE |
TC_CMR_BCPB_NONE | TC_CMR_BCPC_NONE | TC_CMR_BEEVT_NONE |
TC_CMR_BSWTRG_NONE);
freerun->tch = sam_tc_allocate(chan, cmr);
if (!freerun->tch)
{
tmrerr("ERROR: Failed to allocate timer channel %d\n", chan);
return -EBUSY;
}
/* Initialize the remaining fields in the state structure and return
* success.
*/
freerun->chan = chan;
freerun->running = false;
freerun->overflow = 0;
/* Set up to receive the callback when the counter overflow occurs */
(void)sam_tc_attach(freerun->tch, sam_freerun_handler, freerun,
TC_INT_COVFS);
/* Start the counter */
sam_tc_start(freerun->tch);
return OK;
}
int sam_oneshot_initialize(struct sam_oneshot_s *oneshot, int chan,
uint16_t resolution)
{
uint32_t frequency;
uint32_t actual;
uint32_t cmr;
int ret;
tmrinfo("chan=%d resolution=%d usec\n", chan, resolution);
DEBUGASSERT(oneshot && resolution > 0);
/* Get the TC frequency the corresponds to the requested resolution */
frequency = USEC_PER_SEC / (uint32_t)resolution;
/* The pre-calculate values to use when we start the timer */
ret = sam_tc_clockselect(frequency, &cmr, &actual);
if (ret < 0)
{
tmrerr("ERROR: sam_tc_clockselect failed: %d\n", ret);
return ret;
}
tmrinfo("frequency=%lu, actual=%lu, cmr=%08lx\n",
(unsigned long)frequency, (unsigned long)actual,
(unsigned long)cmr);
/* Allocate the timer/counter and select its mode of operation
*
* TC_CMR_TCCLKS - Returned by sam_tc_clockselect
* TC_CMR_CLKI=0 - Not inverted
* TC_CMR_BURST_NONE - Not gated by an external signal
* TC_CMR_CPCSTOP=1 - Stop the clock on an RC compare event
* TC_CMR_CPCDIS=0 - Don't disable the clock on an RC compare event
* TC_CMR_EEVTEDG_NONE - No external events (and, hence, no edges
* TC_CMR_EEVT_TIOB - ???? REVISIT
* TC_CMR_ENET=0 - External event trigger disabled
* TC_CMR_WAVSEL_UPRC - TC_CV is incremented from 0 to the value of RC,
* then automatically reset on a RC Compare
* TC_CMR_WAVE - Waveform mode
* TC_CMR_ACPA_NONE - RA compare has no effect on TIOA
* TC_CMR_ACPC_NONE - RC compare has no effect on TIOA
* TC_CMR_AEEVT_NONE - No external event effect on TIOA
* TC_CMR_ASWTRG_NONE - No software trigger effect on TIOA
* TC_CMR_BCPB_NONE - RB compare has no effect on TIOB
* TC_CMR_BCPC_NONE - RC compare has no effect on TIOB
* TC_CMR_BEEVT_NONE - No external event effect on TIOB
* TC_CMR_BSWTRG_NONE - No software trigger effect on TIOB
*/
cmr |= (TC_CMR_BURST_NONE | TC_CMR_CPCSTOP | TC_CMR_EEVTEDG_NONE |
TC_CMR_EEVT_TIOB | TC_CMR_WAVSEL_UPRC | TC_CMR_WAVE |
TC_CMR_ACPA_NONE | TC_CMR_ACPC_NONE | TC_CMR_AEEVT_NONE |
TC_CMR_ASWTRG_NONE | TC_CMR_BCPB_NONE | TC_CMR_BCPC_NONE |
TC_CMR_BEEVT_NONE | TC_CMR_BSWTRG_NONE);
oneshot->tch = sam_tc_allocate(chan, cmr);
if (!oneshot->tch)
{
tmrerr("ERROR: Failed to allocate timer channel %d\n", chan);
return -EBUSY;
}
/* Initialize the remaining fields in the state structure and return
* success.
*/
oneshot->chan = chan;
oneshot->running = false;
oneshot->handler = NULL;
oneshot->arg = NULL;
oneshot->start_count = 0;
return OK;
}