esp32/esp32_rmt: Add initial support for RMT peripheral.

This is an ESP32-specific peripheral so lives in the esp32 module.

ports/esp32/Makefile

@@ -323,6 +323,7 @@ SRC_C = \
 	modsocket.c \
 	modesp.c \
 	esp32_partition.c \
+	esp32_rmt.c \
 	esp32_ulp.c \
 	modesp32.c \
 	espneopixel.c \

ports/esp32/esp32_rmt.c

@@ -0,0 +1,237 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 "Matt Trentini" <matt.trentini@gmail.com>
+ *
+ * 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 "py/runtime.h"
+#include "modmachine.h"
+#include "mphalport.h"
+#include "driver/rmt.h"
+
+// This exposes the ESP32's RMT module to MicroPython. RMT is provided by the Espressif ESP-IDF:
+//
+//    https://docs.espressif.com/projects/esp-idf/en/latest/api-reference/peripherals/rmt.html
+//
+// With some examples provided:
+//
+//    https://github.com/espressif/arduino-esp32/tree/master/libraries/ESP32/examples/RMT
+//
+// RMT allows accurate (down to 12.5ns resolution) transmit - and receive - of pulse signals.
+// Originally designed to generate infrared remote control signals, the module is very
+// flexible and quite easy-to-use.
+//
+// This current MicroPython implementation lacks some major features, notably receive pulses
+// and carrier output.
+
+// Forward declaration
+extern const mp_obj_type_t esp32_rmt_type;
+
+typedef struct _esp32_rmt_obj_t {
+    mp_obj_base_t base;
+    uint8_t channel_id;
+    gpio_num_t pin;
+    uint8_t clock_div;
+    mp_uint_t num_items;
+    rmt_item32_t* items;
+} esp32_rmt_obj_t;
+
+// Defined in machine_time.c; simply added the error message
+// Fixme: Should use this updated error hadline more widely in the ESP32 port.
+//        At least update the method in machine_time.c.
+STATIC esp_err_t check_esp_err(esp_err_t code) {
+    if (code) {
+        mp_raise_msg(&mp_type_OSError, esp_err_to_name(code));
+    }
+
+    return code;
+}
+
+STATIC mp_obj_t esp32_rmt_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_id,        MP_ARG_REQUIRED |                  MP_ARG_INT, {.u_int = -1} },
+        { MP_QSTR_pin,       MP_ARG_REQUIRED | MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = mp_const_none} },
+        { MP_QSTR_clock_div,                   MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 8} }, // 100ns resolution
+    };
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    mp_arg_parse_all_kw_array(n_args, n_kw, all_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
+    mp_uint_t channel_id = args[0].u_int;
+    gpio_num_t pin_id = machine_pin_get_id(args[1].u_obj);
+    mp_uint_t clock_div = args[2].u_int;
+
+    if (clock_div < 1 || clock_div > 255) {
+        mp_raise_ValueError("clock_div must be between 1 and 255");
+    }
+
+    esp32_rmt_obj_t *self = m_new_obj_with_finaliser(esp32_rmt_obj_t);
+    self->base.type = &esp32_rmt_type;
+    self->channel_id = channel_id;
+    self->pin = pin_id;
+    self->clock_div = clock_div;
+
+    rmt_config_t config;
+    config.rmt_mode = RMT_MODE_TX;
+    config.channel = (rmt_channel_t) self->channel_id;
+    config.gpio_num = self->pin;
+    config.mem_block_num = 1;
+    config.tx_config.loop_en = 0;
+
+    config.tx_config.carrier_en = 0;
+    config.tx_config.idle_output_en = 1;
+    config.tx_config.idle_level = 0;
+    config.tx_config.carrier_duty_percent = 0;
+    config.tx_config.carrier_freq_hz = 0;
+    config.tx_config.carrier_level = 1;
+
+    config.clk_div = self->clock_div;
+
+    check_esp_err(rmt_config(&config));
+    check_esp_err(rmt_driver_install(config.channel, 0, 0));
+
+    return MP_OBJ_FROM_PTR(self);
+}
+
+STATIC void esp32_rmt_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
+    esp32_rmt_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    if (self->pin != -1) {
+        mp_printf(print, "RMT(channel=%u, pin=%u, source_freq=%u, clock_div=%u)",
+            self->channel_id, self->pin, APB_CLK_FREQ, self->clock_div);
+    } else {
+        mp_printf(print, "RMT()");
+    }
+}
+
+STATIC mp_obj_t esp32_rmt_deinit(mp_obj_t self_in) {
+    // fixme: check for valid channel. Return exception if error occurs.
+    esp32_rmt_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    if (self->pin != -1) { // Check if channel has already been deinitialised.
+        rmt_driver_uninstall(self->channel_id);
+        self->pin = -1; // -1 to indicate RMT is unused
+        m_free(self->items);
+    }
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(esp32_rmt_deinit_obj, esp32_rmt_deinit);
+
+// Return the source frequency.
+// Currently only the APB clock (80MHz) can be used but it is possible other
+// clock sources will added in the future.
+STATIC mp_obj_t esp32_rmt_source_freq(mp_obj_t self_in) {
+    return mp_obj_new_int(APB_CLK_FREQ);
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(esp32_rmt_source_freq_obj, esp32_rmt_source_freq);
+
+// Return the clock divider.
+STATIC mp_obj_t esp32_rmt_clock_div(mp_obj_t self_in) {
+    esp32_rmt_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    return mp_obj_new_int(self->clock_div);
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(esp32_rmt_clock_div_obj, esp32_rmt_clock_div);
+
+// Query whether the channel has finished sending pulses. Takes an optional
+// timeout (in ticks of the 80MHz clock), returning true if the pulse stream has
+// completed or false if they are still transmitting (or timeout is reached).
+STATIC mp_obj_t esp32_rmt_wait_done(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_self,    MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = mp_const_none} },
+        { MP_QSTR_timeout, MP_ARG_KW_ONLY  | MP_ARG_INT, {.u_int = 0} },
+    };
+
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
+
+    esp32_rmt_obj_t *self = MP_OBJ_TO_PTR(args[0].u_obj);
+
+    esp_err_t err = rmt_wait_tx_done(self->channel_id, args[1].u_int);
+    return err == ESP_OK ? mp_const_true : mp_const_false;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_KW(esp32_rmt_wait_done_obj, 1, esp32_rmt_wait_done);
+
+STATIC mp_obj_t esp32_rmt_loop(mp_obj_t self_in, mp_obj_t loop) {
+    esp32_rmt_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    check_esp_err(rmt_set_tx_loop_mode(self->channel_id, mp_obj_get_int(loop)));
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_2(esp32_rmt_loop_obj, esp32_rmt_loop);
+
+STATIC mp_obj_t esp32_rmt_write_pulses(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_self,   MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = mp_const_none} },
+        { MP_QSTR_pulses, MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = mp_const_none} },
+        { MP_QSTR_start,  MP_ARG_KW_ONLY  | MP_ARG_INT, {.u_int = 1} },
+    };
+
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
+
+    esp32_rmt_obj_t *self = MP_OBJ_TO_PTR(args[0].u_obj);
+    mp_obj_t pulses = args[1].u_obj;
+    mp_uint_t start = args[2].u_int;
+
+    if (start < 0 || start > 1) {
+        mp_raise_ValueError("start must be 0 or 1");
+    }
+
+    size_t pulses_length = 0;
+    mp_obj_t* pulses_ptr = NULL;
+    mp_obj_get_array(pulses, &pulses_length, &pulses_ptr);
+
+    mp_uint_t num_items = (pulses_length / 2) + (pulses_length % 2);
+    if (num_items > self->num_items) {
+        self->items = (rmt_item32_t*)m_realloc(self->items, num_items * sizeof(rmt_item32_t *));
+        self->num_items = num_items;
+    }
+
+    for (mp_uint_t item_index = 0; item_index < num_items; item_index++) {
+        mp_uint_t pulse_index = item_index * 2;
+        self->items[item_index].duration0 = mp_obj_get_int(pulses_ptr[pulse_index++]);
+        self->items[item_index].level0 = start++; // Note that start _could_ wrap.
+        if (pulse_index < pulses_length) {
+            self->items[item_index].duration1 = mp_obj_get_int(pulses_ptr[pulse_index]);
+            self->items[item_index].level1 = start++;
+        }
+    }
+    check_esp_err(rmt_write_items(self->channel_id, self->items, num_items, false /* non-blocking */));
+
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_KW(esp32_rmt_write_pulses_obj, 2, esp32_rmt_write_pulses);
+
+STATIC const mp_rom_map_elem_t esp32_rmt_locals_dict_table[] = {
+    { MP_ROM_QSTR(MP_QSTR___del__), MP_ROM_PTR(&esp32_rmt_deinit_obj) },
+    { MP_ROM_QSTR(MP_QSTR_deinit), MP_ROM_PTR(&esp32_rmt_deinit_obj) },
+    { MP_ROM_QSTR(MP_QSTR_source_freq), MP_ROM_PTR(&esp32_rmt_source_freq_obj) },
+    { MP_ROM_QSTR(MP_QSTR_clock_div), MP_ROM_PTR(&esp32_rmt_clock_div_obj) },
+    { MP_ROM_QSTR(MP_QSTR_wait_done), MP_ROM_PTR(&esp32_rmt_wait_done_obj) },
+    { MP_ROM_QSTR(MP_QSTR_loop), MP_ROM_PTR(&esp32_rmt_loop_obj) },
+    { MP_ROM_QSTR(MP_QSTR_write_pulses), MP_ROM_PTR(&esp32_rmt_write_pulses_obj) },
+};
+STATIC MP_DEFINE_CONST_DICT(esp32_rmt_locals_dict, esp32_rmt_locals_dict_table);
+
+const mp_obj_type_t esp32_rmt_type = {
+    { &mp_type_type },
+    .name = MP_QSTR_RMT,
+    .print = esp32_rmt_print,
+    .make_new = esp32_rmt_make_new,
+    .locals_dict = (mp_obj_dict_t*)&esp32_rmt_locals_dict,
+};

ports/esp32/modesp32.c

@@ -155,6 +155,7 @@ STATIC const mp_rom_map_elem_t esp32_module_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR_hall_sensor), MP_ROM_PTR(&esp32_hall_sensor_obj) },
 
     { MP_ROM_QSTR(MP_QSTR_Partition), MP_ROM_PTR(&esp32_partition_type) },
+    { MP_ROM_QSTR(MP_QSTR_RMT), MP_ROM_PTR(&esp32_rmt_type) },
     { MP_ROM_QSTR(MP_QSTR_ULP), MP_ROM_PTR(&esp32_ulp_type) },
 
     { MP_ROM_QSTR(MP_QSTR_WAKEUP_ALL_LOW), MP_ROM_PTR(&mp_const_false_obj) },

ports/esp32/modesp32.h

@@ -27,6 +27,7 @@
 #define RTC_IS_VALID_EXT_PIN(pin_id) ((1ll << (pin_id)) & RTC_VALID_EXT_PINS)
 
 extern const mp_obj_type_t esp32_partition_type;
+extern const mp_obj_type_t esp32_rmt_type;
 extern const mp_obj_type_t esp32_ulp_type;
 
 #endif // MICROPY_INCLUDED_ESP32_MODESP32_H