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/*
* 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;
}
}
}
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