1 files changed, 244 insertions, 0 deletions
diff --git a/circuitpython/ports/raspberrypi/common-hal/pulseio/PulseIn.c b/circuitpython/ports/raspberrypi/common-hal/pulseio/PulseIn.c
new file mode 100644
index 0000000..45d3162
--- /dev/null
+++ b/circuitpython/ports/raspberrypi/common-hal/pulseio/PulseIn.c
@@ -0,0 +1,244 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2021 Dave Putz 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 "src/rp2_common/hardware_gpio/include/hardware/gpio.h"
+
+#include <stdint.h>
+
+#include "py/runtime.h"
+#include "shared-bindings/microcontroller/__init__.h"
+#include "shared-bindings/pulseio/PulseIn.h"
+#include "shared-bindings/microcontroller/Pin.h"
+#include "supervisor/shared/translate.h"
+#include "bindings/rp2pio/StateMachine.h"
+#include "common-hal/pulseio/PulseIn.h"
+
+#define NO_PIN 0xff
+#define MAX_PULSE 65535
+#define MIN_PULSE 10
+
+uint16_t pulsein_program[] = {
+    0x4001, //  1: in     pins, 1
+};
+
+void common_hal_pulseio_pulsein_construct(pulseio_pulsein_obj_t *self,
+    const mcu_pin_obj_t *pin, uint16_t maxlen, bool idle_state) {
+
+    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"), maxlen * sizeof(uint16_t));
+    }
+    self->pin = pin->number;
+    self->maxlen = maxlen;
+    self->idle_state = idle_state;
+    self->start = 0;
+    self->len = 0;
+
+    bool ok = rp2pio_statemachine_construct(&self->state_machine,
+        pulsein_program, sizeof(pulsein_program) / sizeof(pulsein_program[0]),
+        1000000,
+        NULL, 0,
+        NULL, 0,
+        pin, 1,
+        0,0,
+        NULL, 0,
+        NULL, 0,
+        1, 0,
+        NULL, // jump pin
+        1 << self->pin, false, true,
+            false, 8, false, // TX, unused
+            false,
+            true, 32, true, // RX auto-push every 32 bits
+            false, // claim pins
+            false, // Not user-interruptible.
+            false, // No sideset enable
+            0, -1); // wrap settings
+
+    if (!ok) {
+        mp_raise_RuntimeError(translate("All state machines in use"));
+    }
+
+    pio_sm_set_enabled(self->state_machine.pio,self->state_machine.state_machine, false);
+    pio_sm_clear_fifos(self->state_machine.pio,self->state_machine.state_machine);
+    self->last_level = self->idle_state;
+    self->level_count = 0;
+    self->buf_index = 0;
+
+    pio_sm_set_in_pins(self->state_machine.pio,self->state_machine.state_machine,pin->number);
+    common_hal_rp2pio_statemachine_set_interrupt_handler(&(self->state_machine),&common_hal_pulseio_pulsein_interrupt,self,PIO_IRQ0_INTE_SM0_RXNEMPTY_BITS);
+
+    // exec a set pindirs to 0 for input
+    pio_sm_exec(self->state_machine.pio,self->state_machine.state_machine,0xe080);
+    // exec the appropriate wait for pin
+    if (self->idle_state == true) {
+        pio_sm_exec(self->state_machine.pio,self->state_machine.state_machine,0x2020);
+    } else {
+        pio_sm_exec(self->state_machine.pio,self->state_machine.state_machine,0x20a0);
+    }
+    pio_sm_set_enabled(self->state_machine.pio, self->state_machine.state_machine, true);
+}
+
+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;
+    }
+    pio_sm_set_enabled(self->state_machine.pio, self->state_machine.state_machine, false);
+    common_hal_rp2pio_statemachine_deinit(&self->state_machine);
+    m_free(self->buffer);
+    reset_pin_number(self->pin);
+    self->pin = NO_PIN;
+}
+
+void common_hal_pulseio_pulsein_pause(pulseio_pulsein_obj_t *self) {
+    pio_sm_restart(self->state_machine.pio, self->state_machine.state_machine);
+    pio_sm_set_enabled(self->state_machine.pio, self->state_machine.state_machine, false);
+    self->last_level = self->idle_state;
+    self->level_count = 0;
+    self->buf_index = 0;
+}
+void common_hal_pulseio_pulsein_interrupt(void *self_in) {
+    pulseio_pulsein_obj_t *self = self_in;
+
+    uint32_t rxfifo = 0;
+
+    rxfifo = pio_sm_get_blocking(self->state_machine.pio, self->state_machine.state_machine);
+    // translate from fifo to buffer
+    if ((rxfifo == 0 && self->last_level == false) || (rxfifo == 0xffffffff && self->last_level == true)) {
+        self->level_count = self->level_count + 32;
+    } else {
+        for (uint i = 0; i < 32; i++) {
+            bool level = (rxfifo & (1 << i)) >> i;
+            if (level == self->last_level) {
+                self->level_count++;
+            } else {
+                uint32_t result = self->level_count;
+                self->last_level = level;
+                self->level_count = 0;
+                // Pulses that are longer than MAX_PULSE will return MAX_PULSE
+                if (result > MAX_PULSE) {
+                    result = MAX_PULSE;
+                }
+                // return  pulses that are not too short
+                if (result > MIN_PULSE) {
+                    size_t buf_index = (self->start + self->len) % self->maxlen;
+                    self->buffer[buf_index] = (uint16_t)result;
+                    if (self->len < self->maxlen) {
+                        self->len++;
+                    } else {
+                        self->start = (self->start + 1) % self->maxlen;
+                    }
+                    if (self->buf_index < self->maxlen) {
+                        self->buf_index++;
+                    } else {
+                        self->start = 0;
+                        self->buf_index = 0;
+                    }
+                }
+            }
+        }
+    }
+
+// check for a pulse thats too long (MAX_PULSE us) or maxlen reached,  and reset
+    if ((self->level_count > MAX_PULSE) || (self->buf_index >= self->maxlen)) {
+        pio_sm_set_enabled(self->state_machine.pio, self->state_machine.state_machine, false);
+        pio_sm_init(self->state_machine.pio, self->state_machine.state_machine, self->state_machine.offset, &self->state_machine.sm_config);
+        pio_sm_restart(self->state_machine.pio,self->state_machine.state_machine);
+        pio_sm_set_enabled(self->state_machine.pio, self->state_machine.state_machine, true);
+        self->buf_index = 0;
+    }
+}
+void common_hal_pulseio_pulsein_resume(pulseio_pulsein_obj_t *self,
+    uint16_t trigger_duration) {
+    // Send the trigger pulse.
+    if (trigger_duration > 0) {
+        gpio_set_function(self->pin,GPIO_FUNC_SIO);
+        gpio_set_dir(self->pin,true);
+        gpio_put(self->pin, !self->idle_state);
+        common_hal_mcu_delay_us((uint32_t)trigger_duration);
+        gpio_set_function(self->pin,GPIO_FUNC_PIO0);
+        common_hal_mcu_delay_us(125);
+    }
+
+    // Reconfigure the pin for PIO
+    gpio_set_function(self->pin, GPIO_FUNC_PIO0);
+    // exec a wait for the selected pin to change state
+    if (self->idle_state == true) {
+        pio_sm_exec(self->state_machine.pio,self->state_machine.state_machine,0x2020);
+    } else {
+        pio_sm_exec(self->state_machine.pio,self->state_machine.state_machine,0x20a0);
+    }
+    pio_sm_set_enabled(self->state_machine.pio, self->state_machine.state_machine, true);
+}
+
+void common_hal_pulseio_pulsein_clear(pulseio_pulsein_obj_t *self) {
+    self->start = 0;
+    self->len = 0;
+    self->buf_index = 0;
+}
+
+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);
+    }
+    uint16_t value = self->buffer[self->start];
+    self->start = (self->start + 1) % self->maxlen;
+    self->len--;
+    // if we are empty reset buffer pointer and counters
+    if (self->len == 0) {
+        self->start = 0;
+        self->buf_index = 0;
+        self->level_count = 0;
+    }
+    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;
+}
+
+bool common_hal_pulseio_pulsein_get_paused(pulseio_pulsein_obj_t *self) {
+    return true;
+}
+
+uint16_t common_hal_pulseio_pulsein_get_item(pulseio_pulsein_obj_t *self,
+    int16_t index) {
+    if (index < 0) {
+        index += self->len;
+    }
+    if (index < 0 || index >= self->len) {
+        mp_raise_IndexError_varg(translate("%q index out of range"), MP_QSTR_PulseIn);
+    }
+    uint16_t value = self->buffer[(self->start + index) % self->maxlen];
+    return value;
+}