switch to PA0 as BTN

CMakeLists.txt

@@ -12,8 +12,8 @@ set(CMAKE_SYSTEM_NAME Generic)
 set(CMAKE_C_COMPILER avr-gcc)
 set(OBJCOPY avr-objcopy)
 
-# Compiler flags
+# Compiler flags: optimize, warnings, treat warnings as errors
-set(CMAKE_C_FLAGS "-mmcu=${MCU} -DF_CPU=${F_CPU} -Os -Wall")
+set(CMAKE_C_FLAGS "-mmcu=${MCU} -DF_CPU=${F_CPU} -Os -Wall -Werror")
 
 # Sources
 add_executable(main.elf main.c)

main.c

@@ -12,10 +12,11 @@
 /** @defgroup LED_Masks LED bitmasks for PORTA
  *  @{
  */
+#define BUTTON_PIN_MASK 0x01 // PA0
 #define PA1_SET_MASK 0x02    ///< LED 1–2
 #define PA2_SET_MASK 0x04    ///< LED 3–6
 #define PA3_SET_MASK 0x08    ///< LED 7–8
-#define PA6_SET_MASK 0x40 ///< Switch input (was green LED pin) TODO: Switch to PA0
+#define PA6_SET_MASK 0x40    ///< Green LED pin
 #define PA7_SET_MASK 0x80    ///< Red LED
 /** @} */
 
@@ -50,9 +51,9 @@ int main(void)
                   /*PA6_SET_MASK |*/ // PA6 now input (switch)
                   PA7_SET_MASK);
 
-    // Configure PA6 as input with pull-up TODO: Switch to PA0
+    // Configure PA0 as input with pull-up
-    VPORTA.DIR &= ~PA6_SET_MASK;       // Input
+    VPORTA.DIR &= ~BUTTON_PIN_MASK;    // Input
-    PORTA.PIN6CTRL = PORT_PULLUPEN_bm; // Pull-up enabled
+    PORTA.PIN0CTRL = PORT_PULLUPEN_bm; // Pull-up enabled
 
     // --- ensure all LEDs off at startup ---
     leds_off();
@@ -128,7 +129,7 @@ static void handleSwitch(void)
     static uint16_t pressTicks = 0;  ///< press duration counter
     static bool prevPressed = false; ///< previous switch state
 
-    bool pressed = !(VPORTA.IN & PA6_SET_MASK); // active-low
+    bool pressed = !(VPORTA.IN & BUTTON_PIN_MASK); // active-low
 
     if (pressed)
     {