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Fix SAMD21 PulseIn

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Scott Shawcroft 2020-04-02 17:35:52 -07:00
parent 77562a2acd
commit 46af4bdd0e
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GPG Key ID: 9349BC7E64B1921E
1 changed files with 16 additions and 3 deletions
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19
ports/atmel-samd/common-hal/pulseio/PulseIn.c
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@ -48,7 +48,7 @@
static uint8_t refcount = 0; static uint8_t refcount = 0;
static uint8_t pulsein_tc_index = 0xff; 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) { void pulsein_timer_interrupt_handler(uint8_t index) {
if (index != pulsein_tc_index) return; if (index != pulsein_tc_index) return;
@ -91,7 +91,13 @@ void pulsein_interrupt_handler(uint8_t channel) {
self->first_edge = false; self->first_edge = false;
pulsein_set_config(self, false); pulsein_set_config(self, false);
} else { } 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; 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 #ifdef SAMD21
total_diff /= 3; total_diff /= 3;
#endif #endif
@ -133,8 +139,6 @@ void common_hal_pulseio_pulsein_construct(pulseio_pulsein_obj_t* self,
self->start = 0; self->start = 0;
self->len = 0; self->len = 0;
self->first_edge = true; self->first_edge = true;
self->last_overflow = 0;
self->last_count = 0;
self->errored_too_fast = false; self->errored_too_fast = false;
if (refcount == 0) { if (refcount == 0) {
@ -178,11 +182,20 @@ void common_hal_pulseio_pulsein_construct(pulseio_pulsein_obj_t* self,
#endif #endif
tc_set_enable(tc, true); 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; tc->COUNT16.CTRLBSET.reg = TC_CTRLBSET_CMD_RETRIGGER;
//mp_printf(&mp_plat_print, "timer started\n");
overflow_count = 0; overflow_count = 0;
} }
refcount++; refcount++;
self->last_overflow = overflow_count;
self->last_count = 0;
set_eic_channel_data(pin->extint_channel, (void*) self); set_eic_channel_data(pin->extint_channel, (void*) self);