WIPrp2040: Implement IncrementalEncoder

Any two consecutive pins can be used for an IncrementalEncoder

Testing performed: Put a synthesized (few hundred counts per second) quadrature signal into GP2/3 and read the encoder out.  Performed filesystem operations at the same time to stress test it.

The reasons for not using common_hal_rp2pio_statemachine_readinto are commented on.

Author: jepler

ports/raspberrypi/bindings/rp2pio/StateMachine.h

@@ -71,4 +71,6 @@ bool common_hal_rp2pio_statemachine_get_rxstall(rp2pio_statemachine_obj_t* self)
 void common_hal_rp2pio_statemachine_clear_rxfifo(rp2pio_statemachine_obj_t *self);
 size_t common_hal_rp2pio_statemachine_get_in_waiting(rp2pio_statemachine_obj_t *self);
 
+void common_hal_rp2pio_statemachine_set_interrupt_handler(rp2pio_statemachine_obj_t *self, void(*handler)(void*), void *arg, int mask);
+
 #endif // MICROPY_INCLUDED_RASPBERRYPI_BINDINGS_RP2PIO_STATEMACHINE_H

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

@@ -0,0 +1,170 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2018 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "py/runtime.h"
+
+#include <hardware/regs/pio.h>
+#include "common-hal/rotaryio/IncrementalEncoder.h"
+#include "bindings/rp2pio/__init__.h"
+#include "bindings/rp2pio/StateMachine.h"
+
+STATIC const uint16_t encoder[] = {
+    //  again:
+    //      in pins, 2
+    0x4002,
+    //      mov x, isr
+    0xa026,
+    //      jmp x!=y, push_data
+    0x00a5,
+    //      mov isr, null
+    0xa0c3,
+    //      jmp again
+    0x0000,
+    //  push_data:
+    //      push
+    0x8020,
+    //      mov y, x
+    0xa041,
+};
+
+STATIC const uint16_t encoder_init[] = {
+    //      set y, 31
+    0xe05f,
+};
+
+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)};
+    if (!common_hal_rp2pio_pins_are_sequential(2, pins)) {
+        mp_raise_RuntimeError(translate("Pins must be sequential"));
+    }
+
+    self->position = 0;
+    self->quarter_count = 0;
+
+    common_hal_rp2pio_statemachine_construct(&self->state_machine,
+        encoder, MP_ARRAY_SIZE(encoder),
+        1000000,
+        encoder_init, MP_ARRAY_SIZE(encoder_init), // init
+        NULL, 1, 0, 0xffffffff, // out pin
+        pin_a, 2, // in pins
+        3, 0, // in pulls
+        NULL, 0, 0, 0x1f, // set pins
+        NULL, 0, 0, 0x1f, // sideset pins
+        true, // exclusive pin use
+        false, 32, false, // out settings
+        false, // Wait for txstall
+        false, 32, false); // in settings
+
+    common_hal_rp2pio_statemachine_run(&self->state_machine, encoder_init, MP_ARRAY_SIZE(encoder_init));
+
+    // We're guaranteed by the init code that some output will be available promptly
+    uint8_t state;
+    common_hal_rp2pio_statemachine_readinto(&self->state_machine, &state, 1, 1);
+    // Top two bits of self->last_state don't matter, because they'll be gone as soon as
+    // interrupt handler is called.
+    self->last_state = state & 3;
+
+    common_hal_rp2pio_statemachine_set_interrupt_handler(&self->state_machine, incrementalencoder_interrupt_handler, self, PIO_IRQ0_INTF_SM0_RXNEMPTY_BITS);
+}
+
+bool common_hal_rotaryio_incrementalencoder_deinited(rotaryio_incrementalencoder_obj_t* self) {
+    return common_hal_rp2pio_statemachine_deinited(&self->state_machine);
+}
+
+void common_hal_rotaryio_incrementalencoder_deinit(rotaryio_incrementalencoder_obj_t* self) {
+    if (common_hal_rotaryio_incrementalencoder_deinited(self)) {
+        return;
+    }
+    common_hal_rp2pio_statemachine_deinit(&self->state_machine);
+}
+
+mp_int_t common_hal_rotaryio_incrementalencoder_get_position(rotaryio_incrementalencoder_obj_t* self) {
+    return self->position;
+}
+
+void common_hal_rotaryio_incrementalencoder_set_position(rotaryio_incrementalencoder_obj_t* self,
+        mp_int_t new_position) {
+    self->position = new_position;
+}
+
+STATIC void incrementalencoder_interrupt_handler(void *self_in) {
+    rotaryio_incrementalencoder_obj_t* self = self_in;
+    // This table also works for detent both at 11 and 00
+    // For 11 at detent:
+    // Turning cw: 11->01->00->10->11
+    // Turning ccw: 11->10->00->01->11
+    // For 00 at detent:
+    // Turning cw: 00->10->11->10->00
+    // Turning ccw: 00->01->11->10->00
+
+    // index table by state <oldA><oldB><newA><newB>
+    #define BAD 7
+    static const int8_t transitions[16] = {
+        0,    // 00 -> 00 no movement
+        -1,   // 00 -> 01 3/4 ccw (11 detent) or 1/4 ccw (00 at detent)
+        +1,   // 00 -> 10 3/4 cw or 1/4 cw
+        BAD,  // 00 -> 11 non-Gray-code transition
+        +1,   // 01 -> 00 2/4 or 4/4 cw
+        0,    // 01 -> 01 no movement
+        BAD,  // 01 -> 10 non-Gray-code transition
+        -1,   // 01 -> 11 4/4 or 2/4 ccw
+        -1,   // 10 -> 00 2/4 or 4/4 ccw
+        BAD,  // 10 -> 01 non-Gray-code transition
+        0,    // 10 -> 10 no movement
+        +1,   // 10 -> 11 4/4 or 2/4 cw
+        BAD,  // 11 -> 00 non-Gray-code transition
+        +1,   // 11 -> 01 1/4 or 3/4 cw
+        -1,   // 11 -> 10 1/4 or 3/4 ccw
+        0,    // 11 -> 11 no movement
+    };
+
+    while (common_hal_rp2pio_statemachine_get_in_waiting(&self->state_machine)) {
+        // Bypass all the logic of StateMachine.c:_transfer, we need something
+        // very simple and fast for an interrupt!
+        uint8_t new = self->state_machine.pio->rxf[self->state_machine.state_machine];
+
+        // Shift the old AB bits to the "old" position, and set the new AB bits.
+        self->last_state = (self->last_state & 0x3) << 2 | (new & 0x3);
+
+        int8_t quarter_incr = transitions[self->last_state];
+        if (quarter_incr == BAD) {
+            // Missed a transition. We don't know which way we're going, so do nothing.
+            return;
+        }
+
+        self->quarter_count += quarter_incr;
+        if (self->quarter_count >= 4) {
+            self->position += 1;
+            self->quarter_count = 0;
+        } else if (self->quarter_count <= -4) {
+            self->position -= 1;
+            self->quarter_count = 0;
+        }
+    }
+}

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

@@ -0,0 +1,40 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2018 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+#include "common-hal/rp2pio/StateMachine.h"
+#include "common-hal/microcontroller/Pin.h"
+
+#include "py/obj.h"
+
+typedef struct {
+    mp_obj_base_t base;
+    rp2pio_statemachine_obj_t state_machine;
+    uint8_t last_state:4;   // <old A><old B><new A><new B>
+    int8_t quarter_count:4; // count intermediate transitions between detents
+    mp_int_t position;
+} rotaryio_incrementalencoder_obj_t;

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

@@ -0,0 +1 @@
+// No rotaryio module functions.

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

@@ -27,6 +27,7 @@
 #include "bindings/rp2pio/StateMachine.h"
 
 #include "common-hal/microcontroller/__init__.h"
+#include "shared-bindings/microcontroller/__init__.h"
 #include "shared-bindings/microcontroller/Pin.h"
 
 #include "src/rp2040/hardware_regs/include/hardware/platform_defs.h"
@@ -52,6 +53,11 @@ STATIC uint32_t _current_pins[NUM_PIOS];
 STATIC uint32_t _current_sm_pins[NUM_PIOS][NUM_PIO_STATE_MACHINES];
 
 STATIC PIO pio_instances[2] = {pio0, pio1};
+typedef void (*interrupt_handler_type)(void*);
+STATIC interrupt_handler_type _interrupt_handler[NUM_PIOS][NUM_PIO_STATE_MACHINES];
+STATIC void *_interrupt_arg[NUM_PIOS][NUM_PIO_STATE_MACHINES];
+
+STATIC void rp2pio_statemachine_interrupt_handler(void);
 
 static void rp2pio_statemachine_set_pull(uint32_t pull_pin_up, uint32_t pull_pin_down, uint32_t pins_we_use) {
     for (int i=0; i<TOTAL_GPIO_COUNT; i++) {
@@ -100,6 +106,7 @@ void _reset_statemachine(PIO pio, uint8_t sm, bool leave_pins) {
         }
     }
     _current_sm_pins[pio_index][sm] = 0;
+    pio->inte0 &= ~((PIO_IRQ0_INTF_SM0_RXNEMPTY_BITS | PIO_IRQ0_INTF_SM0_TXNFULL_BITS | PIO_IRQ0_INTF_SM0_BITS) << sm);
     pio_sm_unclaim(pio, sm);
 }
 
@@ -535,6 +542,10 @@ void common_hal_rp2pio_statemachine_set_frequency(rp2pio_statemachine_obj_t* sel
 void rp2pio_statemachine_deinit(rp2pio_statemachine_obj_t *self, bool leave_pins) {
     uint8_t sm = self->state_machine;
     uint8_t pio_index = pio_get_index(self->pio);
+    common_hal_mcu_disable_interrupts();
+    _interrupt_arg[pio_index][sm] = NULL;
+    _interrupt_handler[pio_index][sm] = NULL;
+    common_hal_mcu_enable_interrupts();
     _never_reset[pio_index][sm] = false;
     _reset_statemachine(self->pio, sm, leave_pins);
     self->state_machine = NUM_PIO_STATE_MACHINES;
@@ -757,3 +768,34 @@ size_t common_hal_rp2pio_statemachine_get_in_waiting(rp2pio_statemachine_obj_t *
     uint8_t level = pio_sm_get_rx_fifo_level(self->pio, self->state_machine);
     return level;
 }
+
+void common_hal_rp2pio_statemachine_set_interrupt_handler(rp2pio_statemachine_obj_t *self, void(*handler)(void*), void *arg, int mask) {
+    uint8_t pio_index = pio_get_index(self->pio);
+    uint8_t sm = self->state_machine;
+
+    common_hal_mcu_disable_interrupts();
+    uint32_t inte = self->pio->inte0;
+    inte &= ~((PIO_IRQ0_INTF_SM0_RXNEMPTY_BITS | PIO_IRQ0_INTF_SM0_TXNFULL_BITS | PIO_IRQ0_INTF_SM0_BITS) << sm);
+    inte |= (mask << sm);
+    self->pio->inte0 = inte;
+    _interrupt_arg[pio_index][sm] = arg;
+    _interrupt_handler[pio_index][sm] = handler;
+    irq_set_exclusive_handler(PIO0_IRQ_0 + 2 * pio_index, rp2pio_statemachine_interrupt_handler);
+    irq_set_enabled(PIO0_IRQ_0 + 2 * pio_index, true);
+    common_hal_mcu_enable_interrupts();
+}
+
+STATIC void rp2pio_statemachine_interrupt_handler(void) {
+    for (size_t pio_index = 0; pio_index < NUM_PIOS; pio_index++) {
+        PIO pio = pio_instances[pio_index];
+        for (size_t sm = 0; sm < NUM_PIO_STATE_MACHINES; sm++) {
+            if (!_interrupt_handler[pio_index][sm]) {
+                continue;
+            }
+            uint32_t intf = (PIO_IRQ0_INTF_SM0_RXNEMPTY_BITS | PIO_IRQ0_INTF_SM0_TXNFULL_BITS | PIO_IRQ0_INTF_SM0_BITS) << sm;
+            if (pio->ints0 & intf) {
+                _interrupt_handler[pio_index][sm](_interrupt_arg[pio_index][sm]);
+            }
+        }
+    }
+}

ports/raspberrypi/common-hal/rp2pio/StateMachine.c

@@ -28,13 +28,14 @@ CIRCUITPY_FULL_BUILD = 1
 CIRCUITPY_BITOPS = 1
 CIRCUITPY_PWMIO = 1
 CIRCUITPY_RGBMATRIX = 1
+CIRCUITPY_ROTARYIO = 1
 
 # Things that need to be implemented.
+# (Remember to remove any comment when changing a 0 to a 1, make gets confused otherwise)
 CIRCUITPY_FREQUENCYIO = 0 # Use PWM interally
 CIRCUITPY_I2CPERIPHERAL = 0
 CIRCUITPY_NVM = 1
 CIRCUITPY_PULSEIO = 0 # Use PIO interally
-CIRCUITPY_ROTARYIO = 0 # Use PIO interally
 CIRCUITPY_WATCHDOG = 1
 
 # Audio via PWM