Merge pull request 'Disable unused peripherals for power saving' (#5) from feature/energy-saving into main

Reviewed-on: #5

README.md

@@ -76,7 +76,7 @@ Hardware: FT232 USB-UART adapter connected to UPDI with a 4.7 kΩ resistor.
    ```
 4. Flash using pymcuprog:
    ```bash
-    pymcuprog -t uart -u /dev/ttyUSB0 -d attiny202 write -f build/main.hex
+    pymcuprog -t uart -u /dev/ttyUSB0 -d attiny202 erase && pymcuprog -t uart -u /dev/ttyUSB0 -d attiny202 write -f build/main.hex
    ```
 ## Hardware Setup (FT232 → ATtiny202 UPDI)
    ```bash

main.c

@@ -8,8 +8,10 @@
 #include <stdbool.h>
 #include <avr/io.h>
 #include <util/delay.h>
+#include <avr/sleep.h>
+#include <avr/interrupt.h>
 
-#define BUTTON_PIN_MASK 0x01 // PA0 TODO: using RESET/UPDI pin
+#define BUTTON_PIN_MASK 0x01 // PA0 used as RESET/UPDI pin
 #define PA1_SET_MASK 0x02    ///< LED 1–2
 #define PA2_SET_MASK 0x04    ///< LED 3–6
 #define PA3_SET_MASK 0x08    ///< LED 7–8
@@ -18,43 +20,70 @@
 
 #define MAIN_LOOP_SLEEP 10U                 // Main loop delay in ms
 #define BUTTON_LONG_PRESS_DURATION_MS 1000U // Long press threshold
-#define BUTTON_IGNORE_DURATION_MS 1000U     // Time button ignored after long press
+#define BUTTON_SHORT_PRESS_DURATION_MS 50U  // Short press threshold
+#define BUTTON_IGNORE_DURATION_MS 2000U     // Time button ignored after long press
+#define BUTTON_CONFIRMATION_BLINK_LOOPS 10U // Blink animation for confirmation
+#define BUTTON_CONFIRMATION_BLINK_DURATION_MS 50U
+#define GLOW_BRIGHTNESS_MIN 10U
+#define GLOW_BRIGHTNESS_MAX 100U
 
 /** Convert milliseconds to system ticks */
 #define MS_TO_TICKS(ms) ((ms) / MAIN_LOOP_SLEEP)
 
+typedef enum _Mode
+{
+    ANIMATION_BLINK,
+    ANIMATION_GLOW,
+    STATIC_FULL,
+    MAX_COUNT,
+} eMode;
+
 /** Global flags */
 volatile bool bLedEnabled = true;
 volatile bool bBtnPressed = false;
+volatile eMode eModeCurrent = ANIMATION_BLINK;
 
 // Forward declarations
-void blinkLed(bool resetCounters);
+ISR(PORTA_PORT_vect);
+static void software_reset(void);
+static void configureLowPower(void);
+void initPWM(void);
+void setPWM_PA2(uint8_t duty);
 static inline void leds_off(void);
 static inline void leds_on(void);
 static void battery_level_indicator(void);
-static void handleSwitch(void);
+static bool handleSwitch(void);
+static inline void switchMode(void);
+void ledAnimationBlink(bool resetCounters);
+void ledAnimationGlow(void);
+void ledStaticFull(void);
 
 /**
  * @brief Main entry point
  */
 int main(void)
 {
+
+    // Disable unused peripherals for power saving
+    configureLowPower();
+
     // Configure LED pins as outputs
     VPORTA.DIR = (PA1_SET_MASK | PA2_SET_MASK | PA3_SET_MASK | PA6_SET_MASK | PA7_SET_MASK);
+    initPWM();
 
     // Configure PA0 as input with pull-up
     VPORTA.DIR &= ~BUTTON_PIN_MASK;    // Input
     PORTA.PIN0CTRL = PORT_PULLUPEN_bm; // Pull-up enabled
 
-    // Ensure all LEDs off at startup
+    leds_off();                // Ensure all LEDs off at startup
-    leds_off();
     battery_level_indicator(); // TODO: Implement
 
     bool bLedEnabledOld = bLedEnabled;
+    eModeCurrent = ANIMATION_BLINK; // Set the mode to start with
 
     while (true)
     {
-        handleSwitch(); // Check switch state
+        bBtnPressed = handleSwitch(); // Check switch state
 
         // Light LEDs while button is pressed
         if (bBtnPressed)
@@ -66,38 +95,148 @@ int main(void)
             leds_off();
         }
 
-        // Long press detected → show confirmation blink
+        // Long press detected --> show confirmation blink
         if (bLedEnabledOld != bLedEnabled)
         {
             bLedEnabledOld = bLedEnabled;
 
+            for (uint8_t i = 0U; i < BUTTON_CONFIRMATION_BLINK_LOOPS; i++)
+            {
                 leds_off();
-            _delay_ms(BUTTON_IGNORE_DURATION_MS / 10);
+                _delay_ms(BUTTON_CONFIRMATION_BLINK_DURATION_MS);
                 leds_on();
-            _delay_ms(BUTTON_IGNORE_DURATION_MS / 10);
+                _delay_ms(BUTTON_CONFIRMATION_BLINK_DURATION_MS);
                 leds_off();
+            }
+
+            // Give time until button is released
             _delay_ms(BUTTON_IGNORE_DURATION_MS);
 
-            blinkLed(true); // reset blink state machine
+            // Activate the interrupt for PA0
+            PORTA.PIN0CTRL = PORT_PULLUPEN_bm | PORT_ISC_FALLING_gc;
+
+            set_sleep_mode(SLEEP_MODE_STANDBY); // Deepest sleep mode (standby)
+            sleep_enable();                     // Enable sleep
+
+            sei();       // Re-enable interrupts
+            sleep_cpu(); // MCU sleeps here
         }
         else
         {
             if (bLedEnabled && !bBtnPressed)
             {
-                blinkLed(false); // run normal blink
+                switch (eModeCurrent)
+                {
+                case ANIMATION_BLINK:
+                    ledAnimationBlink(false); // run normal blink
+                    break;
+                case ANIMATION_GLOW:
+                    ledAnimationGlow();
+                    break;
+                case STATIC_FULL:
+                    ledStaticFull();
+                    break;
+                default:
+                    break;
+                }
             }
         }
 
+        // Sleep during delay instead of busy-wait
+        sleep_enable();
         _delay_ms(MAIN_LOOP_SLEEP);
+        sleep_disable();
     }
 }
 
+/**
+ * @brief Move to next mode
+ */
+static inline void switchMode(void)
+{
+    eModeCurrent = (eModeCurrent + 1) % MAX_COUNT;
+}
+
+/**
+ * @brief Configure for lowest power consumption
+ */
+static void configureLowPower(void)
+{
+    // Set unused pins as outputs LOW to prevent floating inputs
+    // Floating inputs can cause extra current consumption
+    PORTA.DIRSET = PIN4_bm | PIN5_bm; // Set PA4, PA5 as outputs if unused
+    PORTA.OUTCLR = PIN4_bm | PIN5_bm; // Drive them LOW
+
+    // Configure sleep mode
+    set_sleep_mode(SLEEP_MODE_IDLE); // Use IDLE when TCA0 PWM needs to run
+    // Use SLEEP_MODE_STANDBY for deep sleep when LEDs are off
+
+    // Disable unused timers
+    TCB0.CTRLA = 0; // Disable TCB0 if not used
+    // TCA0 is used for PWM, keep it enabled
+
+    // Disable ADC (Analog-to-Digital Converter)
+    ADC0.CTRLA &= ~ADC_ENABLE_bm;
+
+    // Disable AC (Analog Comparator)
+    AC0.CTRLA &= ~AC_ENABLE_bm;
+
+    // Disable unused USART
+    USART0.CTRLB = 0;
+
+    // Disable TWI (I2C) if not used
+    TWI0.MCTRLA = 0;
+    TWI0.SCTRLA = 0;
+
+    // Disable SPI
+    SPI0.CTRLA = 0;
+
+    // Disable Watchdog Timer (if not needed)
+    // Note: WDT can only be disabled during first 4 clock cycles after reset
+    // CCP = CCP_IOREG_gc;
+    // WDT.CTRLA = 0;
+
+    // Disable BOD (Brown-Out Detection) in sleep modes for lower power
+    // This is done via fuses, not runtime configurable
+
+    // Disable digital input buffers on unused pins to save power
+    // Only needed if pins are truly unused (floating)
+    // PORTA.PIN4CTRL = PORT_ISC_INPUT_DISABLE_gc;  // PA4 if unused
+    // PORTA.PIN5CTRL = PORT_ISC_INPUT_DISABLE_gc;  // PA5 if unused
+}
+
+/**
+ * @brief Init PWM for PA2
+ */
+void initPWM(void)
+{
+    // No PORTMUX needed - PA2 is WO2 by default
+
+    // TCA0 in normal mode (single slope PWM)
+    TCA0.SINGLE.CTRLB = TCA_SINGLE_CMP2EN_bm | TCA_SINGLE_WGMODE_SINGLESLOPE_gc;
+
+    // Set period for ~19.5kHz PWM (5MHz / 256 = ~19.5kHz)
+    TCA0.SINGLE.PER = 0xFF;
+
+    // Start timer with DIV1 (no prescaler)
+    TCA0.SINGLE.CTRLA = TCA_SINGLE_CLKSEL_DIV1_gc | TCA_SINGLE_ENABLE_bm;
+}
+
+/**
+ * @brief Set PWM duty cycle for PA2
+ */
+void setPWM_PA2(uint8_t duty)
+{
+    TCA0.SINGLE.CMP2 = duty;
+}
+
 /**
  * @brief Turn off all controlled LEDs (PA1, PA2, PA3)
  */
 static inline void leds_off(void)
 {
-    VPORTA.OUT &= (uint8_t) ~(PA1_SET_MASK | PA2_SET_MASK | PA3_SET_MASK);
+    VPORTA.OUT &= (uint8_t) ~(PA1_SET_MASK | PA3_SET_MASK);
+    setPWM_PA2(0U);
 }
 
 /**
@@ -105,7 +244,8 @@ static inline void leds_off(void)
  */
 static inline void leds_on(void)
 {
-    VPORTA.OUT |= (PA1_SET_MASK | PA2_SET_MASK | PA3_SET_MASK);
+    VPORTA.OUT |= (PA1_SET_MASK | PA3_SET_MASK);
+    setPWM_PA2(255U);
 }
 
 /**
@@ -120,9 +260,10 @@ static void battery_level_indicator(void)
 /**
  * @brief Handle momentary switch input on PA0
  *
- * A long press toggles ::bLedEnabled.
+ * A long press toggles bLedEnabled.
+ * A short press swiches the mode.
  */
-static void handleSwitch(void)
+static bool handleSwitch(void)
 {
     static uint16_t pressTicks = 0;  ///< Press duration counter
     static bool prevPressed = false; ///< Previous button state
@@ -131,22 +272,58 @@ static void handleSwitch(void)
 
     if (pressed)
     {
-        bBtnPressed = true;
         if (pressTicks < 0xFFFF)
             pressTicks++; // Prevent overflow
     }
     else
     {
-        bBtnPressed = false;
+        // Button released
+        if (prevPressed)
+        {
+            // Check if it was a short press (not a long press)
+            if (pressTicks >= MS_TO_TICKS(BUTTON_SHORT_PRESS_DURATION_MS) &&
+                pressTicks < MS_TO_TICKS(BUTTON_LONG_PRESS_DURATION_MS))
+            {
+                switchMode();
+            }
+        }
+
         pressTicks = 0;
     }
 
-    if (prevPressed && pressTicks >= MS_TO_TICKS(BUTTON_LONG_PRESS_DURATION_MS))
+    if (pressed && pressTicks >= MS_TO_TICKS(BUTTON_LONG_PRESS_DURATION_MS))
     {
         bLedEnabled = !bLedEnabled; // Toggle LED blinking
     }
 
     prevPressed = pressed;
+    return pressed;
+}
+
+/**
+ * @brief Perform software reset
+ */
+static void software_reset(void)
+{
+    CCP = CCP_IOREG_gc; // unlock protected registers
+    RSTCTRL.SWRR = 1;   // trigger software reset
+    while (1)
+        ; // wait for reset
+}
+
+/**
+ * @brief Interrupt service routine
+ */
+ISR(PORTA_PORT_vect)
+{
+    // Clear interrupt flags for PA0
+    PORTA.INTFLAGS = BUTTON_PIN_MASK;
+
+    if (!(VPORTA.IN & BUTTON_PIN_MASK)) // check PA0 low
+    {
+        // Turn off all LEDs
+        software_reset();
+    }
 }
 
 /**
@@ -164,7 +341,7 @@ static void handleSwitch(void)
  *   18: all off, wait 250 ms → restart
  * Special: every 3rd cycle, all LEDs ON for 250 ms
  */
-void blinkLed(bool resetCounters)
+void ledAnimationBlink(bool resetCounters)
 {
     const uint8_t T50 = MS_TO_TICKS(50);
     const uint8_t T100 = MS_TO_TICKS(100);
@@ -231,7 +408,7 @@ void blinkLed(bool resetCounters)
         break;
 
     case 12: // LED 3–6 on, wait 50 ms
-        VPORTA.OUT |= PA2_SET_MASK;
+        setPWM_PA2(255U);
         if (counter >= T50)
         {
             counter = 0;
@@ -249,7 +426,7 @@ void blinkLed(bool resetCounters)
         break;
 
     case 16: // LED 3–6 on, wait 50 ms
-        VPORTA.OUT |= PA2_SET_MASK;
+        setPWM_PA2(255U);
         if (counter >= T50)
         {
             counter = 0;
@@ -275,7 +452,7 @@ void blinkLed(bool resetCounters)
         break;
 
     case 20: // special: all LEDs on for 250 ms
-        VPORTA.OUT |= (PA1_SET_MASK | PA2_SET_MASK | PA3_SET_MASK);
+        leds_on();
         if (counter >= T250)
         {
             counter = 0;
@@ -284,3 +461,38 @@ void blinkLed(bool resetCounters)
         break;
     }
 }
+
+/**
+ * @brief All LEDs with static full power
+ */
+void ledStaticFull(void)
+{
+    leds_on();
+}
+
+/**
+ * @brief Inner LEDs with glow animation
+ */
+void ledAnimationGlow(void)
+{
+    static uint8_t brightness = 0;
+    static int8_t direction = 1;
+
+    // Update brightness level every call (10ms)
+    brightness += direction;
+
+    // Reverse direction at limits
+    if (brightness >= GLOW_BRIGHTNESS_MAX)
+    {
+        brightness = GLOW_BRIGHTNESS_MAX;
+        direction = -1;
+    }
+    else if (brightness == GLOW_BRIGHTNESS_MIN)
+    {
+        brightness = GLOW_BRIGHTNESS_MIN;
+        direction = 1;
+    }
+
+    // Apply PWM brightness to LED 3-6
+    setPWM_PA2(brightness * 255 / 100); // Scale 0-100 to 0-255
+}