From 599b61c08687ca077e3b0e115d5b76affcc673ca Mon Sep 17 00:00:00 2001 From: Jim Mussared Date: Thu, 11 Nov 2021 23:36:27 +1100 Subject: [PATCH] esp32/machine_bitstream: Replace bit-bang code with RMT-based driver. This aims to solve glitching issues on long neopixel strips. Signed-off-by: Jim Mussared --- ports/esp32/esp32_rmt.c | 6 ++ ports/esp32/machine_bitstream.c | 138 ++++++++++++++++++++++---------- ports/esp32/modesp32.h | 3 + 3 files changed, 104 insertions(+), 43 deletions(-) diff --git a/ports/esp32/esp32_rmt.c b/ports/esp32/esp32_rmt.c index 37ecef324877..1a7e77b9d23f 100644 --- a/ports/esp32/esp32_rmt.c +++ b/ports/esp32/esp32_rmt.c @@ -29,6 +29,8 @@ #include "mphalport.h" #include "driver/rmt.h" +#include "modesp32.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 @@ -73,6 +75,10 @@ STATIC mp_obj_t esp32_rmt_make_new(const mp_obj_type_t *type, size_t n_args, siz mp_uint_t idle_level = args[3].u_bool; mp_obj_t tx_carrier_obj = args[4].u_obj; + if (channel_id == MICROPY_HW_ESP32_RMT_CHANNEL_BITSTREAM) { + mp_raise_ValueError(MP_ERROR_TEXT("reserved channel id")); + } + if (clock_div < 1 || clock_div > 255) { mp_raise_ValueError(MP_ERROR_TEXT("clock_div must be between 1 and 255")); } diff --git a/ports/esp32/machine_bitstream.c b/ports/esp32/machine_bitstream.c index 9d2bb5724615..9854b83434e4 100644 --- a/ports/esp32/machine_bitstream.c +++ b/ports/esp32/machine_bitstream.c @@ -24,63 +24,115 @@ * THE SOFTWARE. */ -// This is a translation of the cycle counter implementation in ports/stm32/machine_bitstream.c. - #include "py/mpconfig.h" #include "py/mphal.h" #if MICROPY_PY_MACHINE_BITSTREAM -#define NS_TICKS_OVERHEAD (6) +#include "driver/rmt.h" -void IRAM_ATTR machine_bitstream_high_low(mp_hal_pin_obj_t pin, uint32_t *timing_ns, const uint8_t *buf, size_t len) { - uint32_t pin_mask, gpio_reg_set, gpio_reg_clear; - #if !CONFIG_IDF_TARGET_ESP32C3 - if (pin >= 32) { - pin_mask = 1 << (pin - 32); - gpio_reg_set = GPIO_OUT1_W1TS_REG; - gpio_reg_clear = GPIO_OUT1_W1TC_REG; - } else - #endif - { - pin_mask = 1 << pin; - gpio_reg_set = GPIO_OUT_W1TS_REG; - gpio_reg_clear = GPIO_OUT_W1TC_REG; - } +#include "modesp32.h" - // Convert ns to cpu ticks [high_time_0, period_0, high_time_1, period_1]. - uint32_t fcpu_mhz = ets_get_cpu_frequency(); - for (size_t i = 0; i < 4; ++i) { - timing_ns[i] = fcpu_mhz * timing_ns[i] / 1000; - if (timing_ns[i] > NS_TICKS_OVERHEAD) { - timing_ns[i] -= NS_TICKS_OVERHEAD; - } - if (i % 2 == 1) { - // Convert low_time to period (i.e. add high_time). - timing_ns[i] += timing_ns[i - 1]; - } +#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 - uint32_t irq_state = mp_hal_quiet_timing_enter(); +// 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 }}}; - for (size_t i = 0; i < len; ++i) { - uint8_t b = buf[i]; - for (size_t j = 0; j < 8; ++j) { - GPIO_REG_WRITE(gpio_reg_set, pin_mask); - uint32_t start_ticks = mp_hal_ticks_cpu(); - uint32_t *t = &timing_ns[b >> 6 & 2]; - while (mp_hal_ticks_cpu() - start_ticks < t[0]) { - ; - } - GPIO_REG_WRITE(gpio_reg_clear, pin_mask); - b <<= 1; - while (mp_hal_ticks_cpu() - start_ticks < t[1]) { - ; +// 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++; } - mp_hal_quiet_timing_exit(irq_state); + *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)); } #endif // MICROPY_PY_MACHINE_BITSTREAM diff --git a/ports/esp32/modesp32.h b/ports/esp32/modesp32.h index 18bd62ee4164..86979f0b3e06 100644 --- a/ports/esp32/modesp32.h +++ b/ports/esp32/modesp32.h @@ -31,4 +31,7 @@ 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; +// Reserve the last channel for machine.bitstream. +#define MICROPY_HW_ESP32_RMT_CHANNEL_BITSTREAM (RMT_CHANNEL_MAX - 1) + #endif // MICROPY_INCLUDED_ESP32_MODESP32_H