localhorst/WS2812B-LED-RC-Controller
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support SBUS instead PWM

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This commit is contained in:
Hendrik Schutter
2026-02-14 21:42:46 +01:00
parent 5cc2bd0b1d
commit 4ccfc5128b
3 changed files with 237 additions and 3 deletions
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4
main/control.c
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@ -13,6 +13,7 @@
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_log.h"
#include "driver/gpio.h"
static const char *TAG = "CONTROL";
static uint8_t current_animation_mode = 0;
@ -64,6 +65,9 @@ esp_err_t control_init(void)
return ret;
}
// Start ISR service
ESP_ERROR_CHECK(gpio_install_isr_service(0));
// Initialize RC signal
ret = rcsignal_init(current_config.pwm_pin);
if (ret != ESP_OK)

213
main/rcsignal.c
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@ -11,39 +11,78 @@
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#ifdef USE_SBUS_MODE
#include "driver/uart.h"
#endif
#include <string.h>
static const char *TAG = "RCSIGNAL";
#ifdef USE_SBUS_MODE
// SBUS protocol constants
#define SBUS_FRAME_SIZE 25
#define SBUS_HEADER 0x0F
#define SBUS_FOOTER 0x00
#define SBUS_FOOTER2 0x04 // Alternative footer
#define SBUS_BAUDRATE 100000
#define SBUS_CH_MIN 172
#define SBUS_CH_CENTER 992
#define SBUS_CH_MAX 1811
#define SBUS_THRESHOLD_LOW 800
#define SBUS_THRESHOLD_HIGH 1100
#define UART_NUM UART_NUM_1
#define UART_BUF_SIZE 256
#else
// PWM mode constants
#define PULSE_THRESHOLD_US 1500
#define SIGNAL_TIMEOUT_MS 100
#endif
static struct
{
int8_t gpio_pin;
#ifdef USE_SBUS_MODE
volatile uint16_t channels[SBUS_NUM_CHANNELS];
volatile int64_t last_frame_time;
volatile bool signal_active;
volatile bool pull_detected;
uint8_t rx_buffer[SBUS_FRAME_SIZE];
#else
volatile uint32_t pulse_width_us;
volatile int64_t last_edge_time;
volatile int64_t pulse_start_time;
volatile bool last_level;
volatile bool signal_active;
volatile bool pull_detected;
#endif
uint8_t current_mode;
rcsignal_mode_change_callback_t callback;
bool initialized;
TaskHandle_t monitor_task;
} rcsignal = {
.gpio_pin = -1,
#ifdef USE_SBUS_MODE
.channels = {0},
.last_frame_time = 0,
.signal_active = false,
.pull_detected = false,
.rx_buffer = {0},
#else
.pulse_width_us = 0,
.last_edge_time = 0,
.pulse_start_time = 0,
.last_level = false,
.signal_active = false,
.pull_detected = false,
#endif
.current_mode = 0,
.callback = NULL,
.initialized = false,
.monitor_task = NULL,
};
#ifndef USE_SBUS_MODE
// PWM Mode: GPIO ISR handler
static void IRAM_ATTR gpio_isr_handler(void *arg)
{
int64_t now = esp_timer_get_time();
@ -67,9 +106,95 @@ static void IRAM_ATTR gpio_isr_handler(void *arg)
rcsignal.last_level = level;
}
#else
// SBUS Mode: Parse SBUS frame
static bool parse_sbus_frame(const uint8_t *frame, uint16_t *channels)
{
// Check header and footer
if (frame[0] != SBUS_HEADER || (frame[24] != SBUS_FOOTER && frame[24] != SBUS_FOOTER2))
{
return false;
}
// SBUS uses 11 bits per channel, packed into bytes
channels[0] = ((frame[1] | frame[2] << 8) & 0x07FF);
channels[1] = ((frame[2] >> 3 | frame[3] << 5) & 0x07FF);
channels[2] = ((frame[3] >> 6 | frame[4] << 2 | frame[5] << 10) & 0x07FF);
channels[3] = ((frame[5] >> 1 | frame[6] << 7) & 0x07FF);
channels[4] = ((frame[6] >> 4 | frame[7] << 4) & 0x07FF);
channels[5] = ((frame[7] >> 7 | frame[8] << 1 | frame[9] << 9) & 0x07FF);
channels[6] = ((frame[9] >> 2 | frame[10] << 6) & 0x07FF);
channels[7] = ((frame[10] >> 5 | frame[11] << 3) & 0x07FF);
channels[8] = ((frame[12] | frame[13] << 8) & 0x07FF);
channels[9] = ((frame[13] >> 3 | frame[14] << 5) & 0x07FF);
channels[10] = ((frame[14] >> 6 | frame[15] << 2 | frame[16] << 10) & 0x07FF);
channels[11] = ((frame[16] >> 1 | frame[17] << 7) & 0x07FF);
channels[12] = ((frame[17] >> 4 | frame[18] << 4) & 0x07FF);
channels[13] = ((frame[18] >> 7 | frame[19] << 1 | frame[20] << 9) & 0x07FF);
channels[14] = ((frame[20] >> 2 | frame[21] << 6) & 0x07FF);
channels[15] = ((frame[21] >> 5 | frame[22] << 3) & 0x07FF);
return true;
}
#endif
static void monitor_task(void *arg)
{
#ifdef USE_SBUS_MODE
while (1)
{
// Read SBUS data from UART
int len = uart_read_bytes(UART_NUM, rcsignal.rx_buffer, SBUS_FRAME_SIZE, pdMS_TO_TICKS(20));
if (len == SBUS_FRAME_SIZE)
{
uint16_t temp_channels[SBUS_NUM_CHANNELS];
if (parse_sbus_frame(rcsignal.rx_buffer, temp_channels))
{
// Copy parsed channels
for (int i = 0; i < SBUS_NUM_CHANNELS; i++)
{
rcsignal.channels[i] = temp_channels[i];
}
rcsignal.last_frame_time = esp_timer_get_time();
rcsignal.signal_active = true;
// Check channel 4 for mode trigger
uint16_t ch4_value = rcsignal.channels[SBUS_TRIGGER_CHANNEL];
// Detect pull low
if (ch4_value < SBUS_THRESHOLD_LOW)
{
rcsignal.pull_detected = true;
}
// Detect rising edge (pull high after low)
if (ch4_value > SBUS_THRESHOLD_HIGH && rcsignal.pull_detected)
{
rcsignal.pull_detected = false;
if (rcsignal.callback)
{
rcsignal.callback();
}
}
}
}
// Check for signal timeout
int64_t now = esp_timer_get_time();
if (rcsignal.signal_active && (now - rcsignal.last_frame_time) > (100 * 1000))
{
rcsignal.signal_active = false;
memset((void *)rcsignal.channels, 0, sizeof(rcsignal.channels));
}
vTaskDelay(pdMS_TO_TICKS(5));
}
#else
// PWM mode
uint32_t last_pulse_width = 0;
while (1)
@ -106,6 +231,7 @@ static void monitor_task(void *arg)
}
}
}
#endif
}
esp_err_t rcsignal_init(int8_t pin)
@ -118,7 +244,31 @@ esp_err_t rcsignal_init(int8_t pin)
rcsignal.gpio_pin = pin;
// Configure GPIO
#ifdef USE_SBUS_MODE
// SBUS Mode: Configure UART with inverted RX
ESP_LOGI(TAG, "Initializing SBUS mode on GPIO%d", pin);
uart_config_t uart_config = {
.baud_rate = SBUS_BAUDRATE,
.data_bits = UART_DATA_8_BITS,
.parity = UART_PARITY_EVEN,
.stop_bits = UART_STOP_BITS_2,
.flow_ctrl = UART_HW_FLOWCTRL_DISABLE,
.source_clk = UART_SCLK_APB,
};
ESP_ERROR_CHECK(uart_param_config(UART_NUM, &uart_config));
ESP_ERROR_CHECK(uart_set_pin(UART_NUM, UART_PIN_NO_CHANGE, pin, UART_PIN_NO_CHANGE, UART_PIN_NO_CHANGE));
ESP_ERROR_CHECK(uart_driver_install(UART_NUM, UART_BUF_SIZE * 2, 0, 0, NULL, 0));
// Set inverted RX for FrSky receivers (they output inverted SBUS)
ESP_ERROR_CHECK(uart_set_line_inverse(UART_NUM, UART_SIGNAL_RXD_INV));
ESP_LOGI(TAG, "SBUS UART configured with inverted RX");
#else
// PWM Mode: Configure GPIO with interrupts
ESP_LOGI(TAG, "Initializing PWM mode on GPIO%d", pin);
gpio_config_t io_conf = {
.pin_bit_mask = (1ULL << pin),
.mode = GPIO_MODE_INPUT,
@ -129,20 +279,24 @@ esp_err_t rcsignal_init(int8_t pin)
ESP_ERROR_CHECK(gpio_config(&io_conf));
// Install ISR service
ESP_ERROR_CHECK(gpio_install_isr_service(0));
ESP_ERROR_CHECK(gpio_isr_handler_add(pin, gpio_isr_handler, NULL));
#endif
// Create monitor task
BaseType_t ret = xTaskCreate(monitor_task, "rcsignal_monitor", 2048, NULL, 5, &rcsignal.monitor_task);
if (ret != pdPASS)
{
#ifdef USE_SBUS_MODE
uart_driver_delete(UART_NUM);
#else
gpio_isr_handler_remove(pin);
gpio_uninstall_isr_service();
#endif
return ESP_FAIL;
}
rcsignal.initialized = true;
ESP_LOGI(TAG, "RC signal initialized on GPIO%d", pin);
ESP_LOGI(TAG, "RC signal initialized successfully");
return ESP_OK;
}
@ -158,10 +312,14 @@ void rcsignal_deinit(void)
rcsignal.monitor_task = NULL;
}
#ifdef USE_SBUS_MODE
uart_driver_delete(UART_NUM);
#else
if (rcsignal.gpio_pin >= 0)
{
gpio_isr_handler_remove(rcsignal.gpio_pin);
}
#endif
rcsignal.initialized = false;
}
@ -173,7 +331,18 @@ void rcsignal_register_callback(rcsignal_mode_change_callback_t callback)
uint32_t rcsignal_get_pulse_width(void)
{
#ifdef USE_SBUS_MODE
// In SBUS mode, return channel 4 value mapped to microseconds
// SBUS: 172-1811 -> PWM: ~1000-2000us
if (rcsignal.signal_active)
{
uint16_t ch_val = rcsignal.channels[SBUS_TRIGGER_CHANNEL];
return 1000 + ((ch_val - SBUS_CH_MIN) * 1000) / (SBUS_CH_MAX - SBUS_CH_MIN);
}
return 0;
#else
return rcsignal.pulse_width_us;
#endif
}
bool rcsignal_is_active(void)
@ -185,3 +354,41 @@ uint8_t rcsignal_get_current_mode(void)
{
return rcsignal.current_mode;
}
#ifdef USE_SBUS_MODE
uint16_t rcsignal_get_sbus_channel(uint8_t channel)
{
if (channel >= SBUS_NUM_CHANNELS)
{
return 0;
}
return rcsignal.channels[channel];
}
void rcsignal_debug_print_channels(void)
{
if (!rcsignal.signal_active)
{
ESP_LOGW(TAG, "No SBUS signal active");
return;
}
ESP_LOGI(TAG, "SBUS Channels:");
ESP_LOGI(TAG, " CH1: %4d CH2: %4d CH3: %4d CH4: %4d",
rcsignal.channels[0], rcsignal.channels[1],
rcsignal.channels[2], rcsignal.channels[3]);
ESP_LOGI(TAG, " CH5: %4d CH6: %4d CH7: %4d CH8: %4d",
rcsignal.channels[4], rcsignal.channels[5],
rcsignal.channels[6], rcsignal.channels[7]);
ESP_LOGI(TAG, " CH9: %4d CH10: %4d CH11: %4d CH12: %4d",
rcsignal.channels[8], rcsignal.channels[9],
rcsignal.channels[10], rcsignal.channels[11]);
ESP_LOGI(TAG, " CH13: %4d CH14: %4d CH15: %4d CH16: %4d",
rcsignal.channels[12], rcsignal.channels[13],
rcsignal.channels[14], rcsignal.channels[15]);
// Highlight the trigger channel
ESP_LOGI(TAG, "Trigger channel (CH%d): %d", SBUS_TRIGGER_CHANNEL + 1,
rcsignal.channels[SBUS_TRIGGER_CHANNEL]);
}
#endif

23
main/rcsignal.h
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@ -11,6 +11,15 @@
#include <stdint.h>
#include <stdbool.h>
// Define to switch between PWM and SBUS mode
// Comment out to use PWM mode, uncomment to use SBUS mode
#define USE_SBUS_MODE
#ifdef USE_SBUS_MODE
#define SBUS_NUM_CHANNELS 16 // SBUS supports 16 proportional channels
#define SBUS_TRIGGER_CHANNEL 3 // Channel 4 (index 3) for mode trigger
#endif
/**
* @brief Callback function type for mode changes
*/
@ -52,4 +61,18 @@ bool rcsignal_is_active(void);
*/
uint8_t rcsignal_get_current_mode(void);
#ifdef USE_SBUS_MODE
/**
* @brief Get SBUS channel value
* @param channel Channel index (0-15)
* @return Channel value (172-1811) or 0 if invalid
*/
uint16_t rcsignal_get_sbus_channel(uint8_t channel);
/**
* @brief Debug function to print all SBUS channels
*/
void rcsignal_debug_print_channels(void);
#endif
#endif // RCSIGNAL_H