Add PulseIn support which can be used to measure a series of pulse widths.

This is useful for infrared input and DHT sensors.

Author: tannewt

atmel-samd/Makefile

@@ -150,6 +150,8 @@ LIBS = -larm_cortexM0l_math -lsamd21_qtouch_gcc -lm -lgcc -lc
 SRC_ASF = $(addprefix asf/sam0/,\
 	drivers/adc/adc_sam_d_r/adc.c \
 	drivers/dac/dac_sam_d_c/dac.c \
+	drivers/extint/extint_callback.c \
+	drivers/extint/extint_sam_d_r/extint.c \
 	drivers/nvm/nvm.c \
 	drivers/port/port.c \
 	drivers/sercom/i2c/i2c_sam0/i2c_master.c \
@@ -224,6 +226,7 @@ SRC_BINDINGS = \
 	nativeio/AnalogOut.c \
 	nativeio/DigitalInOut.c \
 	nativeio/I2C.c \
+	nativeio/PulseIn.c \
 	nativeio/PulseOut.c \
 	nativeio/PWMOut.c \
 	nativeio/SPI.c \

atmel-samd/asf_conf/conf_extint.h

@@ -0,0 +1,51 @@
+/**
+ * \file
+ *
+ * \brief SAM D21 External Interrupt Driver Configuration Header
+ *
+ * Copyright (C) 2013-2015 Atmel Corporation. All rights reserved.
+ *
+ * \asf_license_start
+ *
+ * \page License
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * 3. The name of Atmel may not be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * 4. This software may only be redistributed and used in connection with an
+ *    Atmel microcontroller product.
+ *
+ * THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
+ * EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ * \asf_license_stop
+ *
+ */
+/*
+ * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ */
+#ifndef CONF_EXTINT_H_INCLUDED
+#define CONF_EXTINT_H_INCLUDED
+
+#  define EXTINT_CLOCK_SOURCE      GCLK_GENERATOR_0
+
+#endif

atmel-samd/common-hal/microcontroller/types.h

@@ -59,6 +59,8 @@ typedef struct {
     mp_obj_base_t base;
     qstr name;
     uint8_t pin;
+    bool has_extint:1;
+    uint8_t extint_channel:7;
     bool has_adc:1;
     enum adc_positive_input adc_input:7;
     bool has_touch:1;

atmel-samd/common-hal/nativeio/PulseIn.c

@@ -0,0 +1,220 @@
+/*
+ * This file is part of the Micro Python 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/nativeio/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 "mpconfigport.h"
+#include "py/gc.h"
+#include "py/runtime.h"
+#include "samd21_pins.h"
+#include "shared-bindings/microcontroller/__init__.h"
+#include "shared-bindings/nativeio/PulseIn.h"
+
+#include "tick.h"
+
+static nativeio_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++) {
+        active_pulseins[i] = NULL;
+        last_ms[i] = 0;
+        last_us[i] = 0;
+    }
+}
+
+static void pulsein_set_config(nativeio_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);
+    uint64_t current_ms = ticks_ms;
+    nativeio_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];
+        if (last_us[self->channel] > current_us) {
+            us_diff = 1000 + current_us - last_us[self->channel];
+        }
+        uint32_t total_diff = us_diff;
+        if (ms_diff > 1) {
+            total_diff += (ms_diff - 1) * 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_nativeio_pulsein_construct(nativeio_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);
+}
+
+void common_hal_nativeio_pulsein_deinit(nativeio_pulsein_obj_t* self) {
+    extint_chan_disable_callback(self->channel, EXTINT_CALLBACK_TYPE_DETECT);
+    active_pulseins[self->channel] = NULL;
+    reset_pin(self->pin);
+}
+
+void common_hal_nativeio_pulsein_pause(nativeio_pulsein_obj_t* self) {
+    extint_chan_disable_callback(self->channel, EXTINT_CALLBACK_TYPE_DETECT);
+}
+
+void common_hal_nativeio_pulsein_resume(nativeio_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);
+        port_pin_set_output_level(self->pin, !self->idle_state);
+        delay_us(trigger_duration);
+        port_pin_set_output_level(self->pin, self->idle_state);
+    }
+
+    // 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_nativeio_pulsein_clear(nativeio_pulsein_obj_t* self) {
+    common_hal_mcu_disable_interrupts();
+    self->start = 0;
+    self->len = 0;
+    common_hal_mcu_enable_interrupts();
+}
+
+uint16_t common_hal_nativeio_pulsein_popleft(nativeio_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_nativeio_pulsein_get_maxlen(nativeio_pulsein_obj_t* self) {
+    return self->maxlen;
+}
+
+uint16_t common_hal_nativeio_pulsein_get_len(nativeio_pulsein_obj_t* self) {
+    return self->len;
+}
+
+uint16_t common_hal_nativeio_pulsein_get_item(nativeio_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;
+}

atmel-samd/common-hal/nativeio/PulseIn.h

@@ -0,0 +1,32 @@
+/*
+ * 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.
+ */
+
+#ifndef __MICROPY_INCLUDED_ATMEL_SAMD_COMMON_HAL_NATIVEIO_PULSEIN_H__
+#define __MICROPY_INCLUDED_ATMEL_SAMD_COMMON_HAL_NATIVEIO_PULSEIN_H__
+
+void pulsein_reset(void);
+
+#endif // __MICROPY_INCLUDED_ATMEL_SAMD_COMMON_HAL_NATIVEIO_PULSEIN_H__

atmel-samd/common-hal/nativeio/types.h

@@ -88,6 +88,25 @@ typedef struct {
     uint32_t current_baudrate;
 } nativeio_spi_obj_t;
 
+typedef struct {
+    mp_obj_base_t base;
+    uint8_t channel;
+    uint8_t pin;
+    uint16_t* buffer;
+    uint16_t maxlen;
+    bool idle_state;
+    volatile uint16_t start;
+    volatile uint16_t len;
+    volatile bool first_edge;
+    uint16_t ticks_per_ms;
+} nativeio_pulsein_obj_t;
+
+typedef struct {
+    mp_obj_base_t base;
+    __IO PORT_PINCFG_Type *pincfg;
+    uint8_t pin;
+} nativeio_pulseout_obj_t;
+
 typedef struct {
     mp_obj_base_t base;
     const mcu_pin_obj_t *pin;
@@ -99,12 +118,6 @@ typedef struct {
     };
 } nativeio_pwmout_obj_t;
 
-typedef struct {
-    mp_obj_base_t base;
-    __IO PORT_PINCFG_Type *pincfg;
-    uint8_t pin;
-} nativeio_pulseout_obj_t;
-
 typedef struct {
     mp_obj_base_t base;
     // Only support TouchIn when external SPI flash is used.