From 0e5b6587a70ba8010155e41b2d18187534b12f801d04225065c08d7a8ea8eb0a Mon Sep 17 00:00:00 2001
From: localhorst <localhorst@mosad.xyz>
Date: Sat, 8 Nov 2025 23:07:29 +0100
Subject: [PATCH] hw pwm is shit

---
 main.c | 93 +++++++++++++++++++++++++++++++++++-----------------------
 1 file changed, 56 insertions(+), 37 deletions(-)

diff --git a/main.c b/main.c
index 00280c9..cdbcfec 100644
--- a/main.c
+++ b/main.c
@@ -44,11 +44,15 @@ volatile eMode eModeCurrent = ANIMATION_BLINK;
 // Forward declarations
 ISR(PORTA_PORT_vect);
 static void software_reset(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 bool handleSwitch(void);
-static inline void toggleMode(void);
+static inline void switchMode(void);
 void ledAnimationBlink(bool resetCounters);
 void ledAnimationGlow(void);
 void ledStaticFull(void);
@@ -59,7 +63,8 @@ void ledStaticFull(void);
 int main(void)
 {
     // Configure LED pins as outputs
-    VPORTA.DIR = (PA1_SET_MASK | PA2_SET_MASK | PA3_SET_MASK | PA6_SET_MASK | PA7_SET_MASK);
+    VPORTA.DIR = (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
@@ -140,17 +145,42 @@ int main(void)
 /**
  * @brief Move to next mode
  */
-static inline void toggleMode(void)
+static inline void switchMode(void)
 {
     eModeCurrent = (eModeCurrent + 1) % MAX_COUNT;
 }
 
+void initPWM(void)
+{
+    // Configure PA2 as output
+    PORTA.DIRSET = PIN2_bm;
+
+    // Remap TCA0 WO0 to alternative pin (PA2)
+    // Check datasheet for correct PORTMUX bit - this is typically:
+    PORTMUX.CTRLC = PORTMUX_TCA00_bm; // or similar bit to route WO0 to PA2
+
+    // TCA0 in normal mode (single slope PWM)
+    TCA0.SINGLE.CTRLB = TCA_SINGLE_CMP0EN_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;
+}
+
+void setPWM_PA2(uint8_t duty)
+{
+    TCA0.SINGLE.CMP0 = 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);
 }
 
 /**
@@ -158,7 +188,8 @@ 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);
 }
 
 /**
@@ -173,7 +204,8 @@ 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 bool handleSwitch(void)
 {
@@ -196,7 +228,7 @@ static bool handleSwitch(void)
             if (pressTicks >= MS_TO_TICKS(BUTTON_SHORT_PRESS_DURATION_MS) &&
                 pressTicks < MS_TO_TICKS(BUTTON_LONG_PRESS_DURATION_MS))
             {
-                toggleMode();
+                switchMode();
             }
         }
 
@@ -320,7 +352,7 @@ void ledAnimationBlink(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;
@@ -338,7 +370,7 @@ void ledAnimationBlink(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;
@@ -364,7 +396,7 @@ void ledAnimationBlink(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;
@@ -383,41 +415,28 @@ void ledStaticFull(void)
 }
 
 /**
- * @brief Outer LEDs with glow animation
+ * @brief Inner LEDs with glow animation
  */
 void ledAnimationGlow(void)
 {
     static uint8_t brightness = 0;
     static int8_t direction = 1;
-    static uint8_t pwm_counter = 0;
 
-    pwm_counter++;
+    // Update brightness level every call (10ms)
+    brightness += direction;
 
-    if (pwm_counter >= 100)
+    // Reverse direction at limits
+    if (brightness >= 100)
     {
-        pwm_counter = 0;
-
-        // Update brightness level
-        brightness += direction;
-
-        if (brightness >= 100)
-        {
-            brightness = 100;
-            direction = -1;
-        }
-        else if (brightness == 0)
-        {
-            direction = 1;
-        }
+        brightness = 100;
+        direction = -1;
+    }
+    else if (brightness == 0)
+    {
+        brightness = 0;
+        direction = 1;
     }
 
-    // Software PWM: compare pwm_counter with brightness
-    if (pwm_counter < brightness)
-    {
-        VPORTA.OUT |= (PA1_SET_MASK | PA3_SET_MASK);
-    }
-    else
-    {
-        VPORTA.OUT &= ~(PA1_SET_MASK | PA3_SET_MASK);
-    }
+    // Apply PWM brightness to LED 3-6
+    setPWM_PA2(brightness * 255 / 100); // Scale 0-100 to 0-255
 }
\ No newline at end of file