Gissio · iROOT · Mar 8, 2026
diff --git a/platform.io/src/measurements/pulses.c b/platform.io/src/measurements/pulses.c
@@ -25,6 +25,9 @@
 static const Menu pulsesMenu;
 static const Menu pulsesIndicationMenu;
 static const Menu pulsesThresholdMenu;
+#if defined(GC03)
+static const Menu pulseLEDColorMenu;
+#endif
 
 static const char *buildRateAlertMenuOption(menu_size_t index);
 
@@ -328,6 +331,51 @@ bool isTubeFaultAlertTriggered(void)
     return pulses.faultAlertTriggered;
 }
 
+// Pulse LED color menu
+
+static const char *onPulseLEDColorMenuGetOption(menu_size_t index, MenuStyle *menuStyle)
+{
+    *menuStyle = (index == settings.pulseLEDColor);
+
+    switch (index)
+    {
+    case PULSE_LED_COLOR_RED:
+        return "Red";
+    case PULSE_LED_COLOR_GREEN:
+        return "Green";
+    case PULSE_LED_COLOR_BLUE:
+        return "Blue";
+    case PULSE_LED_COLOR_CYAN:
+        return "Cyan";
+    case PULSE_LED_COLOR_MAGENTA:
+        return "Magenta";
+    case PULSE_LED_COLOR_YELLOW:
+        return "Yellow";
+    case PULSE_LED_COLOR_WHITE:
+        return "White";
+    case PULSE_LED_COLOR_RAINBOW:
+        return "Rainbow";
+    default:
+        return NULL;
+    }
+}
+
+static void onPulseLEDColorMenuSelect(menu_size_t index)
+{
+    settings.pulseLEDColor = index;
+}
+
+static MenuState pulseLEDColorMenuState;
+
+static const Menu pulseLEDColorMenu = {
+    "LED Color",
+    &pulseLEDColorMenuState,
+    PULSE_LED_COLOR_NUM,
+    onPulseLEDColorMenuGetOption,
+    onPulseLEDColorMenuSelect,
+    showPulsesMenu,
+};
+
 // Pulses indication menu
 
 enum
@@ -340,6 +388,9 @@ enum
 #endif
 #if defined(PULSE_LED) || defined(PULSE_LED_EN)
     PULSEINDICATION_MENU_PULSE_LED,
+#if defined(GC03)
+    PULSEINDICATION_MENU_PULSE_LED_COLOR,
+#endif
 #endif
     PULSEINDICATION_MENU_DISPLAY_FLASH,
 };
@@ -353,6 +404,9 @@ static cstring pulsesIndicationMenuOptions[] = {
 #endif
 #if defined(PULSE_LED) || defined(PULSE_LED_EN)
     STRING_PULSE_LED,
+#if defined(GC03)
+    "LED Color",
+#endif
 #endif
     STRING_DISPLAY_FLASH,
 };
@@ -380,6 +434,13 @@ static const char *onPulsesIndicationMenuGetOption(menu_size_t index, MenuStyle
         *menuStyle = settings.pulseLED;
 
         break;
+
+#if defined(GC03)
+    case PULSEINDICATION_MENU_PULSE_LED_COLOR:
+        *menuStyle = MENUSTYLE_SUBMENU;
+
+        return "LED Color";
+#endif
 #endif
 
     case PULSEINDICATION_MENU_DISPLAY_FLASH:
@@ -420,6 +481,13 @@ static void onPulsesIndicationMenuSelect(menu_size_t index)
         updateLED();
 
         break;
+
+#if defined(GC03)
+    case PULSEINDICATION_MENU_PULSE_LED_COLOR:
+        showMenu(&pulseLEDColorMenu);
+
+        break;
+#endif
 #endif
 
     case PULSEINDICATION_MENU_DISPLAY_FLASH:

diff --git a/platform.io/src/stm32/gc03.h b/platform.io/src/stm32/gc03.h
@@ -97,8 +97,26 @@
 #define VIBRATOR_PORT GPIOB
 #define VIBRATOR_PIN 1
 
-#define PULSE_LED_PORT GPIOB
-#define PULSE_LED_PIN 15
+// Pulse LED is an RGB LED on GC-03
+#define PULSE_LED_R_PORT GPIOB
+#define PULSE_LED_R_PIN 15
+#define PULSE_LED_R_TIMER TIM8
+#define PULSE_LED_R_TIMER_CHANNEL TIM_CH3N
+
+#define PULSE_LED_G_PORT GPIOB
+#define PULSE_LED_G_PIN 14
+#define PULSE_LED_G_TIMER TIM8
+#define PULSE_LED_G_TIMER_CHANNEL TIM_CH2N
+
+#define PULSE_LED_B_PORT GPIOC
+#define PULSE_LED_B_PIN 8
+#define PULSE_LED_B_TIMER TIM8
+#define PULSE_LED_B_TIMER_CHANNEL TIM_CH3
+
+// For compatibility with stm32_led.c, we keep PULSE_LED defined.
+// It will be used to enable/disable the feature.
+#define PULSE_LED_PORT PULSE_LED_R_PORT
+#define PULSE_LED_PIN PULSE_LED_R_PIN
 #define PULSE_LED_ACTIVE_LOW
 
 #define USB_INTERFACE USB

diff --git a/platform.io/src/stm32/stm32_led.c b/platform.io/src/stm32/stm32_led.c
@@ -11,28 +11,218 @@
 
 #include "../peripherals/led.h"
 #include "../stm32/device.h"
+#include "../system/settings.h"
+
+#include "stm32-ext.h"
+#include "stm32.h"
+
 
 #if defined(PULSE_LED)
 
+#if defined(GC03)
+
+// --- Global variables for color control ---
+// Maximum pattern length - 8 ticks (for simplicity)
+static volatile uint8_t current_pattern[8]; 
+static volatile uint8_t current_pattern_len = 0;
+static volatile uint8_t pattern_step = 0;
+static volatile bool use_tdm_mode = false; // Flag: whether to use the timer
+
+// Bitmasks for colors (convenient for code)
+#define COLOR_OFF 0
+#define COLOR_R   1
+#define COLOR_G   2
+#define COLOR_B   4
+
+// TIM8 interrupt handler
+void TIM8_UP_IRQHandler(void)
+{
+    // Clear the interrupt flag
+    if (TIM8->SR & TIM_SR_UIF)
+    {
+        TIM8->SR = ~TIM_SR_UIF;
+
+        // If TDM mode is off (solid color), do nothing in the interrupt
+        if (!use_tdm_mode) return;
+
+        // 1. Turn off ALL diodes (Active Low: 1 = OFF -> BSRR)
+        PULSE_LED_R_PORT->BSRR = get_bitvalue(PULSE_LED_R_PIN);
+        PULSE_LED_G_PORT->BSRR = get_bitvalue(PULSE_LED_G_PIN);
+        PULSE_LED_B_PORT->BSRR = get_bitvalue(PULSE_LED_B_PIN);
+
+        // 2. Get the current color from the pattern
+        uint8_t color = current_pattern[pattern_step];
+
+        // 3. Turn on the required diode (Active Low: 0 = ON -> BRR)
+        if (color & COLOR_R) PULSE_LED_R_PORT->BRR = get_bitvalue(PULSE_LED_R_PIN);
+        if (color & COLOR_G) PULSE_LED_G_PORT->BRR = get_bitvalue(PULSE_LED_G_PIN);
+        if (color & COLOR_B) PULSE_LED_B_PORT->BRR = get_bitvalue(PULSE_LED_B_PIN);
+
+        // 4. Step through the pattern
+        pattern_step++;
+        if (pattern_step >= current_pattern_len) pattern_step = 0;
+    }
+}
+#endif // GC03
+
 void initPulseLED(void)
 {
-    // GPIO
+#if defined(GC03) && defined(PULSE_LED)
+    // Enable clocking
+    set_bits(RCC->APB2ENR, RCC_APB2ENR_IOPBEN | RCC_APB2ENR_IOPCEN | RCC_APB2ENR_TIM8EN);
+    rcc_enable_afio();
+
+    // Configure pins as Push-Pull Output
+    gpio_setup(PULSE_LED_R_PORT, PULSE_LED_R_PIN, GPIO_MODE_OUTPUT_50MHZ_PUSHPULL);
+    gpio_setup(PULSE_LED_G_PORT, PULSE_LED_G_PIN, GPIO_MODE_OUTPUT_50MHZ_PUSHPULL);
+    gpio_setup(PULSE_LED_B_PORT, PULSE_LED_B_PIN, GPIO_MODE_OUTPUT_50MHZ_PUSHPULL);
+
     setPulseLED(false);
 
+    // Configure TIM8
+    // Timer frequency ~4 kHz, so that flickering is not noticeable even with long patterns
+    TIM8->PSC = (APB2TIM_FREQUENCY / 1000000) - 1; 
+    TIM8->ARR = 250 - 1; // 250 µs per step
+
+    set_bits(TIM8->DIER, TIM_DIER_UIE);
+    NVIC_SetPriority(TIM8_UP_IRQn, 0x80); 
+    NVIC_EnableIRQ(TIM8_UP_IRQn);
+    set_bits(TIM8->CR1, TIM_CR1_CEN);
+
+#else // Old code
+    setPulseLED(false);
 #if defined(STM32F0) || defined(STM32G0) || defined(STM32L4)
     gpio_setup_output(PULSE_LED_PORT, PULSE_LED_PIN, GPIO_OUTPUTTYPE_PUSHPULL, GPIO_OUTPUTSPEED_2MHZ, GPIO_PULL_FLOATING);
 #elif defined(STM32F1)
     gpio_setup(PULSE_LED_PORT, PULSE_LED_PIN, GPIO_MODE_OUTPUT_2MHZ_PUSHPULL);
 #endif
+#endif
 }
 
+#if defined(GC03)
+// Helper function for setting a static color
+static void setStaticColor(uint8_t mask) {
+    use_tdm_mode = false;
+
+    // First, turn everything off
+    PULSE_LED_R_PORT->BSRR = get_bitvalue(PULSE_LED_R_PIN);
+    PULSE_LED_G_PORT->BSRR = get_bitvalue(PULSE_LED_G_PIN);
+    PULSE_LED_B_PORT->BSRR = get_bitvalue(PULSE_LED_B_PIN);
+
+    // Turn on the required one (Active Low -> BRR)
+    if (mask & COLOR_R) PULSE_LED_R_PORT->BRR = get_bitvalue(PULSE_LED_R_PIN);
+    if (mask & COLOR_G) PULSE_LED_G_PORT->BRR = get_bitvalue(PULSE_LED_G_PIN);
+    if (mask & COLOR_B) PULSE_LED_B_PORT->BRR = get_bitvalue(PULSE_LED_B_PIN);
+}
+
+// Helper function for setting a pattern
+static void setPattern(const uint8_t* pattern, uint8_t len) {
+    NVIC_DisableIRQ(TIM8_UP_IRQn);
+
+    // Copy the pattern to the global buffer
+    for(int i=0; i<len; i++) current_pattern[i] = pattern[i];
+    current_pattern_len = len;
+    pattern_step = 0;
+    use_tdm_mode = true;
+
+    NVIC_EnableIRQ(TIM8_UP_IRQn);
+}
+
+// Static variable to store the current rainbow step
+static uint8_t rainbow_step = 0;
+#endif
+
 void setPulseLED(bool value)
 {
+#if defined(GC03) && defined(PULSE_LED)
+    if (!value) {
+        setStaticColor(COLOR_OFF);
+        return;
+    }
+
+    // Local variable to determine which color to show now
+    uint8_t color_to_show = settings.pulseLEDColor;
+
+
+    if (color_to_show == PULSE_LED_COLOR_RAINBOW)
+    {
+        // List of colors to cycle through
+        const uint8_t rainbow_sequence[] = {
+            PULSE_LED_COLOR_RED,
+            PULSE_LED_COLOR_YELLOW,
+            PULSE_LED_COLOR_GREEN,
+            PULSE_LED_COLOR_CYAN,
+            PULSE_LED_COLOR_BLUE,
+            PULSE_LED_COLOR_MAGENTA,
+            PULSE_LED_COLOR_WHITE,
+        };
+
+        // Get the color from the list
+        color_to_show = rainbow_sequence[rainbow_step];
+
+        // Prepare the index for the next time
+        rainbow_step++;
+        if (rainbow_step >= sizeof(rainbow_sequence)) {
+            rainbow_step = 0;
+        }
+    }
+
+    // Apply display logic for the selected color
+    switch (color_to_show)
+    {
+    // --- SOLID COLORS (100% Brightness) ---
+    case PULSE_LED_COLOR_RED:
+        setStaticColor(COLOR_R);
+        break;
+    case PULSE_LED_COLOR_GREEN:
+        setStaticColor(COLOR_G);
+        break;
+    case PULSE_LED_COLOR_BLUE:
+        setStaticColor(COLOR_B);
+        break;
+
+    // --- MIXED COLORS (Balance adjustment) ---
+
+    // YELLOW
+    // Pattern: R -> R -> R -> G (75% Red, 25% Green)
+    case PULSE_LED_COLOR_YELLOW: {
+        const uint8_t p[] = {COLOR_R, COLOR_R, COLOR_R, COLOR_G}; 
+        setPattern(p, 4);
+        break;
+    }
+
+    // CYAN
+    // Pattern: G -> B (50% / 50%)
+    case PULSE_LED_COLOR_CYAN: {
+        const uint8_t p[] = {COLOR_G, COLOR_B};
+        setPattern(p, 2);
+        break;
+    }
+
+    // MAGENTA
+    // Pattern: R -> B (50% / 50%)
+    case PULSE_LED_COLOR_MAGENTA: {
+        const uint8_t p[] = {COLOR_R, COLOR_B};
+        setPattern(p, 2);
+        break;
+    }
+
+    // WHITE
+    // Pattern: R -> R -> G -> B (50% Red, 25% Green, 25% Blue)
+    case PULSE_LED_COLOR_WHITE: {
+        const uint8_t p[] = {COLOR_R, COLOR_R, COLOR_G, COLOR_B};
+        setPattern(p, 4);
+        break;
+    }
+    }
+
+#else // For other devices
 #if defined(PULSE_LED_ACTIVE_LOW)
     gpio_modify(PULSE_LED_PORT, PULSE_LED_PIN, !value);
 #else
     gpio_modify(PULSE_LED_PORT, PULSE_LED_PIN, value);
 #endif
+#endif
 }
 
 #endif

diff --git a/platform.io/src/system/settings.c b/platform.io/src/system/settings.c
@@ -38,6 +38,7 @@ Settings settings;
 static const Settings defaultSettings = {
     .pulseSound = true,
     .pulseLED = true,
+    .pulseLEDColor = PULSE_LED_COLOR_GREEN,
 
     .secondaryDoseUnits = DOSE_UNITS_CPM,
 
@@ -123,6 +124,7 @@ static bool validateState(const State *state)
     const Settings *s = &state->settings;
 
     return (!s->empty &&
+            (s->pulseLEDColor < PULSE_LED_COLOR_NUM) &&
             (s->source < SOURCE_NUM) &&
             (s->instantaneousAveraging < INSTANTANEOUSAVERAGING_NUM) &&
             (s->averaging < AVERAGING_NUM) &&