fix nrf ISR; make direction consistent across ports; save code size

Author: dhalbert

ports/atmel-samd/common-hal/rotaryio/IncrementalEncoder.h

@@ -35,10 +35,10 @@ typedef struct {
     mp_obj_base_t base;
     uint8_t pin_a;
     uint8_t pin_b;
-    uint8_t eic_channel_a:4;
-    uint8_t eic_channel_b:4;
-    uint8_t state:4;   // <old A><old B>
-    int8_t quarter_count:4; // count intermediate transitions between detents
+    uint8_t eic_channel_a;
+    uint8_t eic_channel_b;
+    uint8_t state;        // <old A><old B>
+    int8_t quarter_count; // count intermediate transitions between detents
     mp_int_t position;
 } rotaryio_incrementalencoder_obj_t;
 

ports/nrf/common-hal/rotaryio/IncrementalEncoder.c

@@ -41,9 +41,9 @@ static void _intr_handler(nrfx_gpiote_pin_t pin, nrf_gpiote_polarity_t action) {
         return;
     }
 
-    // reads a state 0 .. 3 *in order*.
-    uint8_t new_state = nrf_gpio_pin_read(self->pin_a);
-    new_state = (new_state << 1) + (new_state ^ nrf_gpio_pin_read(self->pin_b));
+    uint8_t new_state =
+        ((uint8_t) nrf_gpio_pin_read(self->pin_a) << 1) |
+        (uint8_t) nrf_gpio_pin_read(self->pin_b);
 
     shared_module_softencoder_state_update(self, new_state);
 }

ports/nrf/common-hal/rotaryio/IncrementalEncoder.h

@@ -35,8 +35,8 @@ typedef struct {
     mp_obj_base_t base;
     uint8_t pin_a;
     uint8_t pin_b;
-    int8_t quarter_count : 4;
-    uint8_t state : 4;
+    uint8_t state;        // <old A><old B>
+    int8_t quarter_count; // count intermediate transitions between detents
     mp_int_t position;
 } rotaryio_incrementalencoder_obj_t;
 

ports/raspberrypi/common-hal/rotaryio/IncrementalEncoder.c

@@ -61,9 +61,12 @@ STATIC void incrementalencoder_interrupt_handler(void *self_in);
 void common_hal_rotaryio_incrementalencoder_construct(rotaryio_incrementalencoder_obj_t *self,
     const mcu_pin_obj_t *pin_a, const mcu_pin_obj_t *pin_b) {
     mp_obj_t pins[] = {MP_OBJ_FROM_PTR(pin_a), MP_OBJ_FROM_PTR(pin_b)};
+    // Start out with swapped to match behavior with other ports.
+    self->swapped = true;
     if (!common_hal_rp2pio_pins_are_sequential(2, pins)) {
         pins[0] = MP_OBJ_FROM_PTR(pin_b);
         pins[1] = MP_OBJ_FROM_PTR(pin_a);
+        self->swapped = false;
         if (!common_hal_rp2pio_pins_are_sequential(2, pins)) {
             mp_raise_RuntimeError(translate("Pins must be sequential"));
         }
@@ -115,6 +118,13 @@ STATIC void incrementalencoder_interrupt_handler(void *self_in) {
         // Bypass all the logic of StateMachine.c:_transfer, we need something
         // very simple and fast for an interrupt!
         uint8_t new_state = self->state_machine.pio->rxf[self->state_machine.state_machine];
+        if (self->swapped) {
+            if (new_state == 0x1) {
+                new_state = 0x2;
+            } else if (new_state == 0x2) {
+                new_state = 0x1;
+            }
+        }
         shared_module_softencoder_state_update(self, new_state);
     }
 }

ports/raspberrypi/common-hal/rotaryio/IncrementalEncoder.h

@@ -34,7 +34,8 @@
 typedef struct {
     mp_obj_base_t base;
     rp2pio_statemachine_obj_t state_machine;
-    uint8_t state : 4;   // <old A><old B><new A><new B>
-    int8_t quarter_count : 4; // count intermediate transitions between detents
+    uint8_t state;        // <old A><old B>
+    int8_t quarter_count; // count intermediate transitions between detents
+    bool swapped;         // Did the pins need to be swapped to be sequential?
     mp_int_t position;
 } rotaryio_incrementalencoder_obj_t;