circuitpython/ports/atmel-samd/common-hal/pulseio/PulseIn.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2017 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 "common-hal/pulseio/PulseIn.h"
#include <stdint.h>
#include "asf/common2/services/delay/delay.h"
#include "asf/sam0/drivers/extint/extint.h"
#include "asf/sam0/drivers/extint/extint_callback.h"
#include "asf/sam0/drivers/port/port.h"
#include "mpconfigport.h"
#include "py/gc.h"
#include "py/runtime.h"
#include "samd21_pins.h"
#include "shared-bindings/microcontroller/__init__.h"
#include "shared-bindings/pulseio/PulseIn.h"
#include "tick.h"
static pulseio_pulsein_obj_t *active_pulseins[EIC_NUMBER_OF_INTERRUPTS];
static uint64_t last_ms[EIC_NUMBER_OF_INTERRUPTS];
static uint16_t last_us[EIC_NUMBER_OF_INTERRUPTS];
void pulsein_reset(void) {
for (int i = 0; i < EIC_NUMBER_OF_INTERRUPTS; i++) {
if (active_pulseins[i] != NULL) {
extint_chan_disable_callback(i, EXTINT_CALLBACK_TYPE_DETECT);
}
active_pulseins[i] = NULL;
last_ms[i] = 0;
last_us[i] = 0;
}
}
static void pulsein_set_config(pulseio_pulsein_obj_t* self, bool first_edge) {
struct extint_chan_conf config;
extint_chan_get_config_defaults(&config);
config.gpio_pin = self->pin;
config.gpio_pin_pull = EXTINT_PULL_NONE;
config.filter_input_signal = true;
if (!first_edge) {
config.detection_criteria = EXTINT_DETECT_BOTH;
} else if (self->idle_state) {
config.detection_criteria = EXTINT_DETECT_FALLING;
} else {
config.detection_criteria = EXTINT_DETECT_RISING;
}
extint_chan_disable_callback(self->channel, EXTINT_CALLBACK_TYPE_DETECT);
extint_chan_set_config(self->channel, &config);
// Clear any interrupts that may have triggered without notifying the CPU.
EIC->INTFLAG.reg |= (1UL << self->channel);
extint_chan_enable_callback(self->channel, EXTINT_CALLBACK_TYPE_DETECT);
}
static void pulsein_callback(void) {
// Grab the current time first.
uint16_t current_us = tc_get_count_value(&ms_timer);
// Add the overflow flag to account for tick interrupts that are blocked by
// this interrupt.
uint64_t current_ms = ticks_ms + TC5->COUNT16.INTFLAG.bit.OVF;
pulseio_pulsein_obj_t* self = active_pulseins[extint_get_current_channel()];
current_us = current_us * 1000 / self->ticks_per_ms;
if (self->first_edge) {
self->first_edge = false;
pulsein_set_config(self, false);
} else {
uint32_t ms_diff = current_ms - last_ms[self->channel];
uint16_t us_diff = current_us - last_us[self->channel];
uint32_t total_diff = us_diff;
if (last_us[self->channel] > current_us) {
total_diff = 1000 + current_us - last_us[self->channel];
if (ms_diff > 1) {
total_diff += (ms_diff - 1) * 1000;
}
} else {
total_diff += ms_diff * 1000;
}
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++;
}
}
last_ms[self->channel] = current_ms;
last_us[self->channel] = current_us;
}
void common_hal_pulseio_pulsein_construct(pulseio_pulsein_obj_t* self,
const mcu_pin_obj_t* pin, uint16_t maxlen, bool idle_state) {
if (!pin->has_extint) {
mp_raise_RuntimeError("No hardware support on pin");
}
// TODO(tannewt): Switch to checking actual extint peripheral state when other
// classes use extints.
if (active_pulseins[pin->extint_channel] != NULL) {
mp_raise_RuntimeError("EXTINT channel already in use");
}
self->buffer = (uint16_t *) gc_alloc(maxlen * sizeof(uint16_t), false);
if (self->buffer == NULL) {
mp_raise_msg_varg(&mp_type_MemoryError, "Failed to allocate RX buffer of %d bytes", maxlen * sizeof(uint16_t));
}
self->channel = pin->extint_channel;
self->pin = pin->pin;
self->maxlen = maxlen;
self->idle_state = idle_state;
self->start = 0;
self->len = 0;
self->first_edge = true;
self->ticks_per_ms = (system_cpu_clock_get_hz() / 1000 - 1);
active_pulseins[pin->extint_channel] = self;
pulsein_set_config(self, true);
extint_register_callback(
pulsein_callback,
self->channel,
EXTINT_CALLBACK_TYPE_DETECT);
extint_chan_enable_callback(self->channel, EXTINT_CALLBACK_TYPE_DETECT);
}
bool common_hal_pulseio_pulsein_deinited(pulseio_pulsein_obj_t* self) {
return self->pin == NO_PIN;
}
void common_hal_pulseio_pulsein_deinit(pulseio_pulsein_obj_t* self) {
if (common_hal_pulseio_pulsein_deinited(self)) {
return;
}
extint_chan_disable_callback(self->channel, EXTINT_CALLBACK_TYPE_DETECT);
active_pulseins[self->channel] = NULL;
reset_pin(self->pin);
self->pin = NO_PIN;
}
void common_hal_pulseio_pulsein_pause(pulseio_pulsein_obj_t* self) {
extint_chan_disable_callback(self->channel, EXTINT_CALLBACK_TYPE_DETECT);
}
void common_hal_pulseio_pulsein_resume(pulseio_pulsein_obj_t* self,
uint16_t trigger_duration) {
// Send the trigger pulse.
if (trigger_duration > 0) {
struct port_config pin_conf;
port_get_config_defaults(&pin_conf);
pin_conf.direction = PORT_PIN_DIR_OUTPUT;
pin_conf.input_pull = PORT_PIN_PULL_NONE;
port_pin_set_config(self->pin, &pin_conf);
// TODO(tannewt): delay_us isn't exactly correct so we adjust the value
// here before calling it. Find out why its not exact and fix it instead
// of hacking around it here.
uint32_t adjusted_duration = trigger_duration;
adjusted_duration *= 4;
adjusted_duration /= 5;
common_hal_mcu_disable_interrupts();
port_pin_set_output_level(self->pin, !self->idle_state);
common_hal_mcu_delay_us(adjusted_duration);
port_pin_set_output_level(self->pin, self->idle_state);
common_hal_mcu_enable_interrupts();
}
// Reconfigure the pin and make sure its set to detect the first edge.
last_ms[self->channel] = 0;
last_us[self->channel] = 0;
self->first_edge = true;
pulsein_set_config(self, true);
}
void common_hal_pulseio_pulsein_clear(pulseio_pulsein_obj_t* self) {
common_hal_mcu_disable_interrupts();
self->start = 0;
self->len = 0;
common_hal_mcu_enable_interrupts();
}
uint16_t common_hal_pulseio_pulsein_popleft(pulseio_pulsein_obj_t* self) {
if (self->len == 0) {
mp_raise_IndexError("pop from an empty PulseIn");
}
common_hal_mcu_disable_interrupts();
uint16_t value = self->buffer[self->start];
self->start = (self->start + 1) % self->maxlen;
self->len--;
common_hal_mcu_enable_interrupts();
return value;
}
uint16_t common_hal_pulseio_pulsein_get_maxlen(pulseio_pulsein_obj_t* self) {
return self->maxlen;
}
uint16_t common_hal_pulseio_pulsein_get_len(pulseio_pulsein_obj_t* self) {
return self->len;
}
uint16_t common_hal_pulseio_pulsein_get_item(pulseio_pulsein_obj_t* self,
int16_t index) {
common_hal_mcu_disable_interrupts();
if (index < 0) {
index += self->len;
}
if (index < 0 || index >= self->len) {
common_hal_mcu_enable_interrupts();
mp_raise_IndexError("index out of range");
}
uint16_t value = self->buffer[(self->start + index) % self->maxlen];
common_hal_mcu_enable_interrupts();
return value;
}