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

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
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* Copyright (c) 2019 Lucian Copeland for Adafruit Industries
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*
* 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/gc.h"
#include "py/runtime.h"
#include "shared-bindings/microcontroller/__init__.h"
#include "shared-bindings/pulseio/PulseIn.h"
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#include "stm32f4xx_hal.h"
#define STM32_GPIO_PORT_SIZE 16
static pulseio_pulsein_obj_t* _objs[STM32_GPIO_PORT_SIZE];
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STATIC TIM_HandleTypeDef t6_handle;
static uint32_t overflow_count = 0;
STATIC uint8_t refcount = 0;
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static void assign_EXTI_Interrupt(pulseio_pulsein_obj_t* self, uint8_t num);
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void TIM6_IRQHandler(void)
{
// Detect TIM Update event
if (__HAL_TIM_GET_FLAG(&t6_handle, TIM_FLAG_UPDATE) != RESET)
{
if (__HAL_TIM_GET_IT_SOURCE(&t6_handle, TIM_IT_UPDATE) != RESET)
{
__HAL_TIM_CLEAR_IT(&t6_handle, TIM_IT_UPDATE);
overflow_count++;
}
}
}
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static void pulsein_handler(uint8_t num) {
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// Grab the current time first.
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uint32_t current_overflow = overflow_count;
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uint32_t current_count = 0;
#if HAS_BASIC_TIM
current_count = TIM6->CNT;
#endif
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// Interrupt register must be cleared manually
EXTI->PR = 1 << num;
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pulseio_pulsein_obj_t* self = _objs[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 {
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uint32_t total_diff = current_count + 0xffff * (current_overflow - self->last_overflow) - self->last_count;
// Cap duration at 16 bits.
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uint16_t duration = 0xffff;
if (total_diff < duration) {
duration = 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++;
}
}
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self->last_count = current_count;
self->last_overflow = current_overflow;
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}
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void pulsein_reset(void) {
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// Disable all active interrupts and clear array
for (uint i = 0; i < STM32_GPIO_PORT_SIZE; i++) {
if (_objs[i] != NULL) {
HAL_NVIC_DisableIRQ(_objs[i]->irq);
}
}
memset(_objs, 0, sizeof(_objs));
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#if HAS_BASIC_TIM
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__HAL_RCC_TIM6_CLK_DISABLE();
refcount = 0;
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#endif
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}
void common_hal_pulseio_pulsein_construct(pulseio_pulsein_obj_t* self, const mcu_pin_obj_t* pin,
uint16_t maxlen, bool idle_state) {
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#if !(HAS_BASIC_TIM)
mp_raise_NotImplementedError(translate("PulseIn not supported on this chip"));
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#else
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// STM32 has one shared EXTI for each pin number, 0-15
uint8_t p_num = pin->number;
if(_objs[p_num]) {
mp_raise_ValueError(translate("Pin number already reserved by EXTI"));
}
_objs[p_num] = self;
// Allocate pulse buffer
self->buffer = (uint16_t *) m_malloc(maxlen * sizeof(uint16_t), false);
if (self->buffer == NULL) {
mp_raise_msg_varg(&mp_type_MemoryError, translate("Failed to allocate RX buffer of %d bytes"),
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maxlen * sizeof(uint16_t));
}
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// 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;
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self->last_count = 0;
self->last_overflow = 0;
if (HAL_TIM_Base_GetState(&t6_handle) == HAL_TIM_STATE_RESET) {
// Set the new period
t6_handle.Instance = TIM6;
t6_handle.Init.Prescaler = 168; // HCLK is 168 mhz so divide down to 1mhz
t6_handle.Init.Period = 0xffff;
HAL_TIM_Base_Init(&t6_handle);
// TIM6 has limited HAL support, set registers manually
t6_handle.Instance->SR = 0; // Prevent the SR from triggering an interrupt
t6_handle.Instance->CR1 |= TIM_CR1_CEN; // Resume timer
t6_handle.Instance->CR1 |= TIM_CR1_URS; // Disable non-overflow interrupts
__HAL_TIM_ENABLE_IT(&t6_handle, TIM_IT_UPDATE);
overflow_count = 0;
}
// Add to active PulseIns
refcount++;
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#endif
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// EXTI pins can also be read as an input
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);
// Interrupt starts immediately
assign_EXTI_Interrupt(self, pin->number);
HAL_NVIC_EnableIRQ(self->irq);
claim_pin(pin);
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}
bool common_hal_pulseio_pulsein_deinited(pulseio_pulsein_obj_t* self) {
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return (self->pin == NULL);
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}
void common_hal_pulseio_pulsein_deinit(pulseio_pulsein_obj_t* self) {
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if (common_hal_pulseio_pulsein_deinited(self)) {
return;
}
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//Remove pulsein slot from shared array
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HAL_NVIC_DisableIRQ(self->irq);
_objs[self->pin->number] = NULL;
reset_pin_number(self->pin->port, self->pin->number);
self->pin = NULL;
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refcount--;
if (refcount == 0) {
#if HAS_BASIC_TIM
__HAL_RCC_TIM6_CLK_DISABLE();
#endif
}
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}
void common_hal_pulseio_pulsein_pause(pulseio_pulsein_obj_t* self) {
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HAL_NVIC_DisableIRQ(self->irq);
self->paused = true;
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}
void common_hal_pulseio_pulsein_resume(pulseio_pulsein_obj_t* self, uint16_t trigger_duration) {
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// 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;
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self->last_count = 0;
self->last_overflow = 0;
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HAL_NVIC_EnableIRQ(self->irq);
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}
void common_hal_pulseio_pulsein_clear(pulseio_pulsein_obj_t* self) {
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HAL_NVIC_DisableIRQ(self->irq);
self->start = 0;
self->len = 0;
HAL_NVIC_EnableIRQ(self->irq);
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}
uint16_t common_hal_pulseio_pulsein_get_item(pulseio_pulsein_obj_t* self, int16_t index) {
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HAL_NVIC_DisableIRQ(self->irq);
if (index < 0) {
index += self->len;
}
if (index < 0 || index >= self->len) {
HAL_NVIC_EnableIRQ(self->irq);
mp_raise_IndexError(translate("index out of range"));
}
uint16_t value = self->buffer[(self->start + index) % self->maxlen];
HAL_NVIC_EnableIRQ(self->irq);
return value;
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}
uint16_t common_hal_pulseio_pulsein_popleft(pulseio_pulsein_obj_t* self) {
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if (self->len == 0) {
mp_raise_IndexError(translate("pop from an empty PulseIn"));
}
HAL_NVIC_DisableIRQ(self->irq);
uint16_t value = self->buffer[self->start];
self->start = (self->start + 1) % self->maxlen;
self->len--;
HAL_NVIC_EnableIRQ(self->irq);
return value;
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}
uint16_t common_hal_pulseio_pulsein_get_maxlen(pulseio_pulsein_obj_t* self) {
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return self->maxlen;
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}
bool common_hal_pulseio_pulsein_get_paused(pulseio_pulsein_obj_t* self) {
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return self->paused;
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}
uint16_t common_hal_pulseio_pulsein_get_len(pulseio_pulsein_obj_t* self) {
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return self->len;
}
static void assign_EXTI_Interrupt(pulseio_pulsein_obj_t* self, uint8_t num) {
if (num == 0) {
self->irq = EXTI0_IRQn;
} else if (num == 1) {
self->irq = EXTI1_IRQn;
} else if (num == 2) {
self->irq = EXTI2_IRQn;
} else if (num == 3) {
self->irq = EXTI3_IRQn;
} else if (num == 4) {
self->irq = EXTI4_IRQn;
} else if (num >= 5 && num <= 9 ) {
self->irq = EXTI9_5_IRQn;
} else if (num >= 10 && num <= 15) {
self->irq = EXTI15_10_IRQn;
}
}
void EXTI0_IRQHandler(void)
{
pulsein_handler(0);
}
void EXTI1_IRQHandler(void)
{
pulsein_handler(1);
}
void EXTI2_IRQHandler(void)
{
pulsein_handler(2);
}
void EXTI3_IRQHandler(void)
{
pulsein_handler(3);
}
void EXTI4_IRQHandler(void)
{
pulsein_handler(4);
}
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void EXTI9_5_IRQHandler(void)
{
uint32_t pending = EXTI->PR;
for (uint i = 5; i <= 9; i++) {
if(pending & (1 << i)) {
pulsein_handler(i);
}
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}
}
void EXTI15_10_IRQHandler(void)
{
uint32_t pending = EXTI->PR;
for (uint i = 10; i <= 15; i++) {
if(pending & (1 << i)) {
pulsein_handler(i);
}
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}
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}