Changed to interrupt guards

Author: jvbroek

ports/raspberrypi/common-hal/pulseio/PulseIn.c

@@ -56,7 +56,6 @@ void common_hal_pulseio_pulsein_construct(pulseio_pulsein_obj_t *self,
     self->idle_state = idle_state;
     self->start = 0;
     self->len = 0;
-    self->len_target = 0;
 
     common_hal_rp2pio_statemachine_construct(&self->state_machine,
         pulsein_program, MP_ARRAY_SIZE(pulsein_program),
@@ -134,8 +133,6 @@ void common_hal_pulseio_pulsein_interrupt(void *self_in) {
                     self->buffer[buf_index] = (uint16_t)result;
                     if (self->len < self->maxlen) {
                         self->len++;
-                        self->len_target++; // The interrupt will only cause a problem in either len or len_target, not both.
-                        // So we can just check for a match, and choose the higher.
                     } else {
                         self->start = (self->start + 1) % self->maxlen;
                     }
@@ -176,14 +173,10 @@ uint16_t common_hal_pulseio_pulsein_popleft(pulseio_pulsein_obj_t *self) {
         mp_raise_IndexError_varg(translate("pop from empty %q"), MP_QSTR_PulseIn);
     }
     uint16_t value = self->buffer[self->start];
+    common_hal_mcu_disable_interrupts();
     self->start = (self->start + 1) % self->maxlen;
-    self->len_target--;
     self->len--;
-    if (self->len != self->len_target) {
-        uint16_t len_accurate = self->len > self->len_target ? self->len : self->len_target;
-        self->len_target = len_accurate;
-        self->len = len_accurate;
-    }
+    common_hal_mcu_enable_interrupts();
     return value;
 }
 

ports/raspberrypi/common-hal/pulseio/PulseIn.h

@@ -43,7 +43,6 @@ typedef struct {
     volatile bool last_level;
     volatile uint32_t level_count;
     volatile uint16_t len;
-    volatile uint16_t len_target;
     volatile uint16_t start;
     rp2pio_statemachine_obj_t state_machine;
 } pulseio_pulsein_obj_t;