diff options
| -rw-r--r-- | ports/atmel-samd/common-hal/pulseio/PulseIn.c | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/ports/atmel-samd/common-hal/pulseio/PulseIn.c b/ports/atmel-samd/common-hal/pulseio/PulseIn.c index d51a67417..4ddee4933 100644 --- a/ports/atmel-samd/common-hal/pulseio/PulseIn.c +++ b/ports/atmel-samd/common-hal/pulseio/PulseIn.c @@ -48,7 +48,7 @@ static uint8_t refcount = 0; static uint8_t pulsein_tc_index = 0xff; -static uint32_t overflow_count = 0; +volatile static uint32_t overflow_count = 0; void pulsein_timer_interrupt_handler(uint8_t index) { if (index != pulsein_tc_index) return; @@ -91,7 +91,13 @@ void pulsein_interrupt_handler(uint8_t channel) { self->first_edge = false; pulsein_set_config(self, false); } else { + // Sometimes we beat the overflow interrupt so just fudge overflow in + // that case. + if (current_count < self->last_count && current_overflow == self->last_overflow) { + current_overflow += 1; + } uint32_t total_diff = current_count + 0xffff * (current_overflow - self->last_overflow) - self->last_count; + // The SAMD21 clock is 48mhz. We prescale it to 3mhz so // 3 here. #ifdef SAMD21 total_diff /= 3; #endif @@ -133,8 +139,6 @@ void common_hal_pulseio_pulsein_construct(pulseio_pulsein_obj_t* self, self->start = 0; self->len = 0; self->first_edge = true; - self->last_overflow = 0; - self->last_count = 0; self->errored_too_fast = false; if (refcount == 0) { @@ -178,11 +182,20 @@ void common_hal_pulseio_pulsein_construct(pulseio_pulsein_obj_t* self, #endif tc_set_enable(tc, true); + + // Clear our interrupt in case it was set earlier + tc->COUNT16.INTFLAG.reg = TC_INTFLAG_OVF; + tc->COUNT16.INTENSET.reg = TC_INTENSET_OVF; + tc_enable_interrupts(pulsein_tc_index); tc->COUNT16.CTRLBSET.reg = TC_CTRLBSET_CMD_RETRIGGER; + //mp_printf(&mp_plat_print, "timer started\n"); + overflow_count = 0; } refcount++; + self->last_overflow = overflow_count; + self->last_count = 0; set_eic_channel_data(pin->extint_channel, (void*) self); |