circuitpython/ports/stm/common-hal/pulseio/PulseIn.c

290 lines
9.9 KiB
C

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2019 Lucian Copeland 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 "common-hal/pulseio/PulseIn.h"
#include <stdint.h>
#include <string.h>
#include "py/mpconfig.h"
#include "py/runtime.h"
#include "shared-bindings/microcontroller/__init__.h"
#include "shared-bindings/microcontroller/Pin.h"
#include "shared-bindings/pulseio/PulseIn.h"
#include "timers.h"
#include "peripherals/exti.h"
#include STM32_HAL_H
#define STM32_GPIO_PORT_SIZE 16
STATIC pulseio_pulsein_obj_t *callback_obj_ref[STM32_GPIO_PORT_SIZE];
STATIC TIM_HandleTypeDef tim_handle;
STATIC uint32_t overflow_count = 0;
STATIC uint8_t refcount = 0;
void pulsein_timer_event_handler(void) {
// Detect TIM Update event
if (__HAL_TIM_GET_FLAG(&tim_handle, TIM_FLAG_UPDATE) != RESET) {
if (__HAL_TIM_GET_IT_SOURCE(&tim_handle, TIM_IT_UPDATE) != RESET) {
__HAL_TIM_CLEAR_IT(&tim_handle, TIM_IT_UPDATE);
overflow_count++;
}
}
}
STATIC void pulsein_exti_event_handler(uint8_t num) {
// Grab the current time first.
uint32_t current_overflow = overflow_count;
uint32_t current_count = tim_handle.Instance->CNT;
// Interrupt register must be cleared manually
#if CPY_STM32L4
EXTI->PR1 = 1 << num;
#else
EXTI->PR = 1 << num;
#endif
pulseio_pulsein_obj_t *self = callback_obj_ref[num];
if (!self) {
return;
}
if (self->first_edge) {
// first pulse is opposite state from idle
bool state = HAL_GPIO_ReadPin(pin_port(self->pin->port), pin_mask(self->pin->number));
if (self->idle_state != state) {
self->first_edge = false;
}
} else {
uint32_t total_diff = current_count + 0x10000 * (current_overflow - self->last_overflow) - self->last_count;
// Cap duration at 16 bits.
uint16_t duration = MIN(0xffff, total_diff);
uint16_t i = (self->start + self->len) % self->maxlen;
self->buffer[i] = duration;
if (self->len < self->maxlen) {
self->len++;
} else {
self->start = (self->start + 1) % self->maxlen;
}
}
self->last_count = current_count;
self->last_overflow = current_overflow;
}
void pulsein_reset(void) {
// Disable all active interrupts and clear array
for (uint i = 0; i < STM32_GPIO_PORT_SIZE; i++) {
if (callback_obj_ref[i] != NULL) {
stm_peripherals_exti_disable(callback_obj_ref[i]->pin->number);
}
}
memset(callback_obj_ref, 0, sizeof(callback_obj_ref));
HAL_TIM_Base_DeInit(&tim_handle);
// tim_clock_disable() takes a bitmask of timers.
tim_clock_disable(1 << stm_peripherals_timer_get_index(tim_handle.Instance));
memset(&tim_handle, 0, sizeof(tim_handle));
refcount = 0;
}
void common_hal_pulseio_pulsein_construct(pulseio_pulsein_obj_t *self, const mcu_pin_obj_t *pin,
uint16_t maxlen, bool idle_state) {
// STM32 has one shared EXTI for each pin number, 0-15
if (!stm_peripherals_exti_is_free(pin->number)) {
mp_raise_RuntimeError(translate("Pin interrupt already in use"));
}
// Allocate pulse buffer
self->buffer = (uint16_t *)m_malloc(maxlen * sizeof(uint16_t), false);
if (self->buffer == NULL) {
// TODO: free the EXTI here?
m_malloc_fail(maxlen * sizeof(uint16_t));
}
// Set internal variables
self->pin = pin;
self->maxlen = maxlen;
self->idle_state = idle_state;
self->start = 0;
self->len = 0;
self->first_edge = true;
self->paused = false;
self->last_count = 0;
self->last_overflow = 0;
if (HAL_TIM_Base_GetState(&tim_handle) == HAL_TIM_STATE_RESET) {
// Find a suitable timer
TIM_TypeDef *tim_instance = stm_peripherals_find_timer();
stm_peripherals_timer_reserve(tim_instance);
// Set ticks to 1us
uint32_t source = stm_peripherals_timer_get_source_freq(tim_instance);
uint32_t prescaler = source / 1000000;
// Enable clocks and IRQ, set callback
stm_peripherals_timer_preinit(tim_instance, 4, pulsein_timer_event_handler);
// Set the new period
tim_handle.Instance = tim_instance;
tim_handle.Init.Prescaler = prescaler - 1;
tim_handle.Init.Period = 0x10000 - 1; // 65 ms period (maximum)
HAL_TIM_Base_Init(&tim_handle);
// Set registers manually
tim_handle.Instance->SR = 0; // Prevent the SR from triggering an interrupt
tim_handle.Instance->CR1 |= TIM_CR1_CEN; // Resume timer
tim_handle.Instance->CR1 |= TIM_CR1_URS; // Disable non-overflow interrupts
__HAL_TIM_ENABLE_IT(&tim_handle, TIM_IT_UPDATE);
overflow_count = 0;
}
// Add to active PulseIns
refcount++;
if (!stm_peripherals_exti_reserve(pin->number)) {
mp_raise_RuntimeError(translate("Pin interrupt already in use"));
}
GPIO_InitTypeDef GPIO_InitStruct = {0};
GPIO_InitStruct.Pin = pin_mask(pin->number);
GPIO_InitStruct.Mode = GPIO_MODE_IT_RISING_FALLING;
GPIO_InitStruct.Pull = GPIO_NOPULL;
HAL_GPIO_Init(pin_port(pin->port), &GPIO_InitStruct);
stm_peripherals_exti_set_callback(pulsein_exti_event_handler, pin->number);
// Store PulseIn object for use in callback
callback_obj_ref[pin->number] = self;
// Interrupt starts immediately
stm_peripherals_exti_enable(pin->number);
common_hal_mcu_pin_claim(pin);
}
bool common_hal_pulseio_pulsein_deinited(pulseio_pulsein_obj_t *self) {
return self->pin == NULL;
}
void common_hal_pulseio_pulsein_deinit(pulseio_pulsein_obj_t *self) {
if (common_hal_pulseio_pulsein_deinited(self)) {
return;
}
// Remove pulsein slot from shared array
callback_obj_ref[self->pin->number] = NULL;
stm_peripherals_exti_free(self->pin->number);
reset_pin_number(self->pin->port, self->pin->number);
self->pin = NULL;
refcount--;
if (refcount == 0) {
stm_peripherals_timer_free(tim_handle.Instance);
}
}
void common_hal_pulseio_pulsein_pause(pulseio_pulsein_obj_t *self) {
stm_peripherals_exti_disable(self->pin->number);
self->paused = true;
}
void common_hal_pulseio_pulsein_resume(pulseio_pulsein_obj_t *self, uint16_t trigger_duration) {
// Make sure we're paused.
if (!self->paused) {
common_hal_pulseio_pulsein_pause(self);
}
// Send the trigger pulse.
if (trigger_duration > 0) {
GPIO_InitTypeDef GPIO_InitStruct = {0};
GPIO_InitStruct.Pin = pin_mask(self->pin->number);
GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
HAL_GPIO_Init(pin_port(self->pin->port), &GPIO_InitStruct);
HAL_GPIO_WritePin(pin_port(self->pin->port), pin_mask(self->pin->number), !self->idle_state);
common_hal_mcu_delay_us((uint32_t)trigger_duration);
HAL_GPIO_WritePin(pin_port(self->pin->port), pin_mask(self->pin->number), self->idle_state);
GPIO_InitStruct.Pin = pin_mask(self->pin->number);
GPIO_InitStruct.Mode = GPIO_MODE_IT_RISING_FALLING;
GPIO_InitStruct.Pull = GPIO_NOPULL;
HAL_GPIO_Init(pin_port(self->pin->port), &GPIO_InitStruct);
}
self->first_edge = true;
self->paused = false;
self->last_count = 0;
self->last_overflow = 0;
stm_peripherals_exti_enable(self->pin->number);
}
void common_hal_pulseio_pulsein_clear(pulseio_pulsein_obj_t *self) {
stm_peripherals_exti_disable(self->pin->number);
self->start = 0;
self->len = 0;
stm_peripherals_exti_enable(self->pin->number);
}
uint16_t common_hal_pulseio_pulsein_get_item(pulseio_pulsein_obj_t *self, int16_t index) {
stm_peripherals_exti_disable(self->pin->number);
if (index < 0) {
index += self->len;
}
if (index < 0 || index >= self->len) {
stm_peripherals_exti_enable(self->pin->number);
mp_raise_IndexError_varg(translate("%q out of range"), MP_QSTR_index);
}
uint16_t value = self->buffer[(self->start + index) % self->maxlen];
stm_peripherals_exti_enable(self->pin->number);
return value;
}
uint16_t common_hal_pulseio_pulsein_popleft(pulseio_pulsein_obj_t *self) {
if (self->len == 0) {
mp_raise_IndexError_varg(translate("pop from empty %q"), MP_QSTR_PulseIn);
}
stm_peripherals_exti_disable(self->pin->number);
uint16_t value = self->buffer[self->start];
self->start = (self->start + 1) % self->maxlen;
self->len--;
stm_peripherals_exti_enable(self->pin->number);
return value;
}
uint16_t common_hal_pulseio_pulsein_get_maxlen(pulseio_pulsein_obj_t *self) {
return self->maxlen;
}
bool common_hal_pulseio_pulsein_get_paused(pulseio_pulsein_obj_t *self) {
return self->paused;
}
uint16_t common_hal_pulseio_pulsein_get_len(pulseio_pulsein_obj_t *self) {
return self->len;
}