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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2021 Jim Mussared
*
* 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/mpconfig.h"
#include "py/mphal.h"
#if MICROPY_PY_MACHINE_BITSTREAM
#include "driver/rmt.h"
#include "modesp32.h"
#if ESP_IDF_VERSION < ESP_IDF_VERSION_VAL(4, 1, 0)
// This convenience macro was not available in earlier IDF versions.
#define RMT_DEFAULT_CONFIG_TX(gpio, channel_id) \
{ \
.rmt_mode = RMT_MODE_TX, \
.channel = channel_id, \
.clk_div = 80, \
.gpio_num = gpio, \
.mem_block_num = 1, \
.tx_config = { \
.loop_en = false, \
.carrier_freq_hz = 38000, \
.carrier_duty_percent = 33, \
.carrier_level = RMT_CARRIER_LEVEL_HIGH, \
.carrier_en = false, \
.idle_level = RMT_IDLE_LEVEL_LOW, \
.idle_output_en = true, \
} \
}
#endif
// Logical 0 and 1 values (encoded as a rmt_item32_t).
// The duration fields will be set later.
STATIC rmt_item32_t bitstream_high_low_0 = {{{ 0, 1, 0, 0 }}};
STATIC rmt_item32_t bitstream_high_low_1 = {{{ 0, 1, 0, 0 }}};
// See https://github.com/espressif/esp-idf/blob/master/examples/common_components/led_strip/led_strip_rmt_ws2812.c
// This is called automatically by the IDF during rmt_write_sample in order to
// convert the byte stream to rmt_item32_t's.
STATIC void IRAM_ATTR bitstream_high_low_rmt_adapter(const void *src, rmt_item32_t *dest, size_t src_size, size_t wanted_num, size_t *translated_size, size_t *item_num) {
if (src == NULL || dest == NULL) {
*translated_size = 0;
*item_num = 0;
return;
}
size_t size = 0;
size_t num = 0;
uint8_t *psrc = (uint8_t *)src;
rmt_item32_t *pdest = dest;
while (size < src_size && num < wanted_num) {
for (int i = 0; i < 8; i++) {
// MSB first
if (*psrc & (1 << (7 - i))) {
pdest->val = bitstream_high_low_1.val;
} else {
pdest->val = bitstream_high_low_0.val;
}
num++;
pdest++;
}
size++;
psrc++;
}
*translated_size = size;
*item_num = num;
}
// Use the reserved RMT channel to stream high/low data on the specified pin.
void machine_bitstream_high_low(mp_hal_pin_obj_t pin, uint32_t *timing_ns, const uint8_t *buf, size_t len) {
rmt_config_t config = RMT_DEFAULT_CONFIG_TX(pin, MICROPY_HW_ESP32_RMT_CHANNEL_BITSTREAM);
// Use 40MHz clock (although 2MHz would probably be sufficient).
config.clk_div = 2;
// Install the driver on this channel & pin.
check_esp_err(rmt_config(&config));
check_esp_err(rmt_driver_install(config.channel, 0, 0));
// Get the tick rate in kHz (this will likely be 40000).
uint32_t counter_clk_khz = 0;
#if ESP_IDF_VERSION < ESP_IDF_VERSION_VAL(4, 1, 0)
uint8_t div_cnt;
check_esp_err(rmt_get_clk_div(config.channel, &div_cnt));
counter_clk_khz = APB_CLK_FREQ / div_cnt;
#else
check_esp_err(rmt_get_counter_clock(config.channel, &counter_clk_khz));
#endif
counter_clk_khz /= 1000;
// Convert nanoseconds to pulse duration.
bitstream_high_low_0.duration0 = (counter_clk_khz * timing_ns[0]) / 1e6;
bitstream_high_low_0.duration1 = (counter_clk_khz * timing_ns[1]) / 1e6;
bitstream_high_low_1.duration0 = (counter_clk_khz * timing_ns[2]) / 1e6;
bitstream_high_low_1.duration1 = (counter_clk_khz * timing_ns[3]) / 1e6;
// Install the bits->highlow translator.
rmt_translator_init(config.channel, bitstream_high_low_rmt_adapter);
// Stream the byte data using the translator.
check_esp_err(rmt_write_sample(config.channel, buf, len, true));
// Wait 50% longer than we expect (if every bit takes the maximum time).
uint32_t timeout_ms = (3 * len / 2) * (1 + (8 * MAX(timing_ns[0] + timing_ns[1], timing_ns[2] + timing_ns[3])) / 1000);
check_esp_err(rmt_wait_tx_done(config.channel, pdMS_TO_TICKS(timeout_ms)));
// Uninstall the driver.
check_esp_err(rmt_driver_uninstall(config.channel));
// Cancel RMT output to GPIO pin.
gpio_matrix_out(pin, SIG_GPIO_OUT_IDX, false, false);
}
#endif // MICROPY_PY_MACHINE_BITSTREAM
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