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Potentiometer based LCD Brightness Control #284

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5a4c9aa
Add ADC potentiometer config for ESP32-S3 target
TadeuBotelho Feb 12, 2026
1746c6f
Add DMG-01 analog volume control via ADC potentiometer
TadeuBotelho Feb 12, 2026
3a6052d
Add ADC potentiometer config for ESP32-S3 target
TadeuBotelho Feb 12, 2026
859fa0c
Add ADC potentiometer config for ESP32-S3 target
TadeuBotelho Feb 12, 2026
9e4356b
Potentiometer-based LCD Brightness Control
TadeuBotelho Feb 13, 2026
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148 changes: 148 additions & 0 deletions components/retro-go/rg_input.c
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Original file line number Diff line number Diff line change
@@ -1,5 +1,7 @@
#include "rg_system.h"
#include "rg_input.h"
#include "rg_audio.h"
#include "rg_display.h"

#include <stdlib.h>
#include <string.h>
Expand Down Expand Up @@ -103,6 +105,58 @@ bool rg_input_read_battery_raw(rg_battery_t *out)
return true;
}

#ifdef RG_POTENTIOMETER_ENABLED
bool rg_input_read_potentiometer_raw(int *out)
{
int raw_value = 0;

#ifdef ESP_PLATFORM
// Read the potentiometer multiple times and average for stability
// This is similar to how battery voltage is read
for (int i = 0; i < 4; ++i)
{
int value = adc_get_raw(RG_POTENTIOMETER_ADC_UNIT, RG_POTENTIOMETER_ADC_CHANNEL);
if (value < 0)
return false;
raw_value += value;
}
raw_value /= 4;
#else
return false;
#endif

if (out)
*out = RG_POTENTIOMETER_CALC_VOLUME(raw_value);
return true;
}
#endif

#ifdef RG_BRIGHTNESS_POTENTIOMETER_ENABLED
bool rg_input_read_brightness_potentiometer_raw(int *out)
{
int raw_value = 0;

#ifdef ESP_PLATFORM
// Read the potentiometer multiple times and average for stability
// This is similar to how battery voltage is read
for (int i = 0; i < 4; ++i)
{
int value = adc_get_raw(RG_BRIGHTNESS_POTENTIOMETER_ADC_UNIT, RG_BRIGHTNESS_POTENTIOMETER_ADC_CHANNEL);
if (value < 0)
return false;
raw_value += value;
}
raw_value /= 4;
#else
return false;
#endif

if (out)
*out = RG_BRIGHTNESS_POTENTIOMETER_CALC_BRIGHTNESS(raw_value);
return true;
}
#endif

bool rg_input_read_gamepad_raw(uint32_t *out)
{
uint32_t state = 0;
Expand Down Expand Up @@ -218,6 +272,14 @@ static void input_task(void *arg)
uint32_t local_gamepad_state = 0;
uint32_t state;
int64_t next_battery_update = 0;
#ifdef RG_POTENTIOMETER_ENABLED
int64_t next_potentiometer_update = 0;
int last_potentiometer_volume = -1000; // Initialize with value that won't match any real volume
#endif
#ifdef RG_BRIGHTNESS_POTENTIOMETER_ENABLED
int64_t next_brightness_potentiometer_update = 0;
int last_brightness_potentiometer_level = -1000; // Initialize with value that won't match any real brightness
#endif

// Start the task with debounce history full to allow a button held during boot to be detected
memset(debounce, 0xFF, sizeof(debounce));
Expand Down Expand Up @@ -258,6 +320,58 @@ static void input_task(void *arg)
next_battery_update = rg_system_timer() + 2 * 1000000; // update every 2 seconds
}

#ifdef RG_POTENTIOMETER_ENABLED
if (rg_system_timer() >= next_potentiometer_update)
{
int potentiometer_volume = 0;
if (rg_input_read_potentiometer_raw(&potentiometer_volume))
{
// Only update volume if change is significant enough (hysteresis)
// This prevents minor ADC fluctuations from constantly updating the volume
if (abs(potentiometer_volume - last_potentiometer_volume) >= RG_POTENTIOMETER_UPDATE_THRESHOLD)
{
// Clamp volume to 0-100% range
int volume = RG_MAX(0, RG_MIN(100, potentiometer_volume));
// Only call rg_audio_set_volume if audio driver is ready (non-null)
// This prevents panic during early boot before audio initialization
if (rg_audio_get_driver() != NULL)
{
rg_audio_set_volume(volume);
last_potentiometer_volume = volume;
RG_LOGD("Potentiometer adjusted volume to %d%%\n", volume);
}
}
}
next_potentiometer_update = rg_system_timer() + RG_POTENTIOMETER_UPDATE_INTERVAL;
}
#endif

#ifdef RG_BRIGHTNESS_POTENTIOMETER_ENABLED
if (rg_system_timer() >= next_brightness_potentiometer_update)
{
int brightness_level = 0;
if (rg_input_read_brightness_potentiometer_raw(&brightness_level))
{
// Only update brightness if change is significant enough (hysteresis)
// This prevents minor ADC fluctuations from constantly updating the brightness
if (abs(brightness_level - last_brightness_potentiometer_level) >= RG_BRIGHTNESS_POTENTIOMETER_UPDATE_THRESHOLD)
{
// Clamp brightness to valid range (1-100, display module has min/max internally)
int brightness = RG_MAX(1, RG_MIN(100, brightness_level));
// Only call rg_display_set_backlight if display driver is ready
// This prevents issues during early boot before display initialization
if (rg_display_get_backlight() >= 0)
{
rg_display_set_backlight(brightness);
last_brightness_potentiometer_level = brightness;
RG_LOGD("Brightness potentiometer adjusted backlight to %d%%\n", brightness);
}
}
}
next_brightness_potentiometer_update = rg_system_timer() + RG_BRIGHTNESS_POTENTIOMETER_UPDATE_INTERVAL;
}
#endif

rg_task_delay(10);
}

Expand Down Expand Up @@ -354,6 +468,40 @@ void rg_input_init(void)
}
#endif

#ifdef RG_POTENTIOMETER_ENABLED
RG_LOGI("Initializing ADC potentiometer driver...");
if (RG_POTENTIOMETER_ADC_UNIT == ADC_UNIT_1)
{
adc1_config_width(ADC_WIDTH_MAX - 1);
adc1_config_channel_atten(RG_POTENTIOMETER_ADC_CHANNEL, RG_POTENTIOMETER_ADC_ATTEN);
}
else if (RG_POTENTIOMETER_ADC_UNIT == ADC_UNIT_2)
{
adc2_config_channel_atten(RG_POTENTIOMETER_ADC_CHANNEL, RG_POTENTIOMETER_ADC_ATTEN);
}
else
{
RG_LOGE("Only ADC1 and ADC2 are supported for potentiometer driver!");
}
#endif

#ifdef RG_BRIGHTNESS_POTENTIOMETER_ENABLED
RG_LOGI("Initializing ADC brightness potentiometer driver...");
if (RG_BRIGHTNESS_POTENTIOMETER_ADC_UNIT == ADC_UNIT_1)
{
adc1_config_width(ADC_WIDTH_MAX - 1);
adc1_config_channel_atten(RG_BRIGHTNESS_POTENTIOMETER_ADC_CHANNEL, RG_BRIGHTNESS_POTENTIOMETER_ADC_ATTEN);
}
else if (RG_BRIGHTNESS_POTENTIOMETER_ADC_UNIT == ADC_UNIT_2)
{
adc2_config_channel_atten(RG_BRIGHTNESS_POTENTIOMETER_ADC_CHANNEL, RG_BRIGHTNESS_POTENTIOMETER_ADC_ATTEN);
}
else
{
RG_LOGE("Only ADC1 and ADC2 are supported for brightness potentiometer driver!");
}
#endif

// The first read returns bogus data in some drivers, waste it.
rg_input_read_gamepad_raw(NULL);

Expand Down
73 changes: 64 additions & 9 deletions components/retro-go/targets/esp32-s3-devkit/config.h
100644 → 100755
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -10,9 +10,10 @@
// #define RG_STORAGE_FLASH_PARTITION "vfs"

// Audio
#define RG_AUDIO_USE_INT_DAC 0 // 0 = Disable, 1 = GPIO25, 2 = GPIO26, 3 = Both
#define RG_AUDIO_USE_INT_DAC 0 // 0 = Disable, 1 = GPIO25, 2 = GPIO26, 3 = Both (Atenção: Apenas ESP32 pussui as portas 25 e 26 podendo ser usadas com o módulo analógico PAM8302 que possuo em estoque. O ESP32S3 é 100% digital.
#define RG_AUDIO_USE_EXT_DAC 1 // 0 = Disable, 1 = Enable


// Video
#define RG_SCREEN_DRIVER 0 // 0 = ILI9341/ST7789
#define RG_SCREEN_HOST SPI2_HOST
Expand Down Expand Up @@ -44,6 +45,8 @@
ILI9341_CMD(0xE1, 0x00, 0x0E, 0x14, 0x03, 0x11, 0x07, 0x31, 0xC1, 0x48, 0x08, 0x0F, 0x0C, 0x31, 0x36, 0x0F);



/* Backup Default Code:
// Input
// Refer to rg_input.h to see all available RG_KEY_* and RG_GAMEPAD_*_MAP types
#define RG_GAMEPAD_ADC_MAP {\
Expand All @@ -52,6 +55,8 @@
{RG_KEY_DOWN, ADC_UNIT_1, ADC_CHANNEL_5, ADC_ATTEN_DB_11, 1024, 3071},\
{RG_KEY_LEFT, ADC_UNIT_1, ADC_CHANNEL_6, ADC_ATTEN_DB_11, 3072, 4096},\
}
*/
/*
#define RG_GAMEPAD_GPIO_MAP {\
{RG_KEY_SELECT, .num = GPIO_NUM_16, .pullup = 1, .level = 0},\
{RG_KEY_START, .num = GPIO_NUM_17, .pullup = 1, .level = 0},\
Expand All @@ -60,27 +65,77 @@
{RG_KEY_A, .num = GPIO_NUM_15, .pullup = 1, .level = 0},\
{RG_KEY_B, .num = GPIO_NUM_5, .pullup = 1, .level = 0},\
}
*/

// D-PAD Map
#define RG_GAMEPAD_GPIO_MAP {\
{RG_KEY_SELECT, .num = GPIO_NUM_16, .pullup = 1, .level = 0},\
{RG_KEY_START, .num = GPIO_NUM_17, .pullup = 1, .level = 0},\
{RG_KEY_MENU, .num = GPIO_NUM_18, .pullup = 1, .level = 0},\
{RG_KEY_OPTION, .num = GPIO_NUM_8, .pullup = 1, .level = 0},\
{RG_KEY_A, .num = GPIO_NUM_15, .pullup = 1, .level = 0},\
{RG_KEY_B, .num = GPIO_NUM_5, .pullup = 1, .level = 0},\
{RG_KEY_UP, .num = GPIO_NUM_2, .pullup = 1, .level = 0},\
{RG_KEY_RIGHT, .num = GPIO_NUM_14, .pullup = 1, .level = 0},\
{RG_KEY_DOWN, .num = GPIO_NUM_45, .pullup = 1, .level = 0},\
{RG_KEY_LEFT, .num = GPIO_NUM_46, .pullup = 1, .level = 0},\
}

// Battery
#define RG_BATTERY_DRIVER 1
#define RG_BATTERY_ADC_UNIT ADC_UNIT_1
#define RG_BATTERY_ADC_CHANNEL ADC_CHANNEL_3
#define RG_BATTERY_ADC_CHANNEL ADC_CHANNEL_3
#define RG_BATTERY_CALC_PERCENT(raw) (((raw) * 2.f - 3500.f) / (4200.f - 3500.f) * 100.f)
#define RG_BATTERY_CALC_VOLTAGE(raw) ((raw) * 2.f * 0.001f)

// Volume Control Potentiometer (GPIO 7 / ADC1_CH6)
// This potentiometer is connected to GPIO 7 and will be read periodically to control audio volume
// The ADC raw value (0-4095) is mapped to volume percentage (0-100%)
#define RG_POTENTIOMETER_ENABLED 1
#define RG_POTENTIOMETER_ADC_UNIT ADC_UNIT_1
#define RG_POTENTIOMETER_ADC_CHANNEL ADC_CHANNEL_6
#define RG_POTENTIOMETER_ADC_ATTEN ADC_ATTEN_DB_11
// Converts raw ADC value (0-4095) to volume percentage (0-100%)
// The formula maps 0V to 0% and 3.3V to 100%
// raw_voltage = (adc_raw * 3.3) / 4095
// volume = (raw_voltage / 3.3) * 100 = (adc_raw / 4095) * 100
#define RG_POTENTIOMETER_CALC_VOLUME(raw) ((int32_t)((raw) * 100 / 4095))
// Hysteresis threshold to prevent volume changes from small ADC fluctuations (in percentage points)
#define RG_POTENTIOMETER_UPDATE_THRESHOLD 5
// Update interval in microseconds (update every 100ms)
#define RG_POTENTIOMETER_UPDATE_INTERVAL (100 * 1000)

// LCD Brightness Control Potentiometer (GPIO 6 / ADC1_CH5)
// This potentiometer is connected to GPIO 6 and will be read periodically to control LCD brightness
// The ADC raw value (0-4095) is mapped to brightness percentage (0-100%)
#define RG_BRIGHTNESS_POTENTIOMETER_ENABLED 1
#define RG_BRIGHTNESS_POTENTIOMETER_ADC_UNIT ADC_UNIT_1
#define RG_BRIGHTNESS_POTENTIOMETER_ADC_CHANNEL ADC_CHANNEL_5
#define RG_BRIGHTNESS_POTENTIOMETER_ADC_ATTEN ADC_ATTEN_DB_11
// Converts raw ADC value (0-4095) to brightness percentage (0-100%)
// The formula maps 0V to 0% and 3.3V to 100%
// raw_voltage = (adc_raw * 3.3) / 4095
// brightness = (raw_voltage / 3.3) * 100 = (adc_raw / 4095) * 100
#define RG_BRIGHTNESS_POTENTIOMETER_CALC_BRIGHTNESS(raw) ((int32_t)((raw) * 100 / 4095))
// Hysteresis threshold to prevent brightness changes from small ADC fluctuations (in percentage points)
#define RG_BRIGHTNESS_POTENTIOMETER_UPDATE_THRESHOLD 5
// Update interval in microseconds (update every 100ms)
#define RG_BRIGHTNESS_POTENTIOMETER_UPDATE_INTERVAL (100 * 1000)


// Status LED
#define RG_GPIO_LED GPIO_NUM_38

// SPI Display (back up working)
#define RG_GPIO_LCD_MISO GPIO_NUM_NC
#define RG_GPIO_LCD_MOSI GPIO_NUM_12
#define RG_GPIO_LCD_CLK GPIO_NUM_48
#define RG_GPIO_LCD_CS GPIO_NUM_NC
#define RG_GPIO_LCD_DC GPIO_NUM_47
#define RG_GPIO_LCD_BCKL GPIO_NUM_39
#define RG_GPIO_LCD_RST GPIO_NUM_3
#define RG_GPIO_LCD_MISO GPIO_NUM_NC // MISO (SDO) ---> Not Connection Where <---
#define RG_GPIO_LCD_MOSI GPIO_NUM_12 // MOSI (SDI / DIN)
#define RG_GPIO_LCD_CLK GPIO_NUM_48 // SCK (CLK)
#define RG_GPIO_LCD_CS GPIO_NUM_NC // GND
#define RG_GPIO_LCD_DC GPIO_NUM_47 // DC (D/C)
#define RG_GPIO_LCD_BCKL GPIO_NUM_39 // LED / BL (BackLight)
#define RG_GPIO_LCD_RST GPIO_NUM_3 // RST (RESET)

// SD Card
#define RG_GPIO_SDSPI_MISO GPIO_NUM_9
#define RG_GPIO_SDSPI_MOSI GPIO_NUM_11
#define RG_GPIO_SDSPI_CLK GPIO_NUM_13
Expand Down
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