From 7bf222228ec8d0cad6b0dcdeccbb57836b934f1d Mon Sep 17 00:00:00 2001
From: Oliver Parczyk <oliver.parczyk@mailbox.tu-dresden.de>
Date: Sat, 16 Dec 2023 12:03:25 +0100
Subject: [PATCH] Fix self driving mode

There was no need to have a timer do the key group switching routine. Not only would that have to be syncronized to the main loop somehow (or run very slowly),
it's also quite an overhead to keep track of.

Just switching to the next key group after we're done scanning the current one, syncronously, works far better (and faster!).
---
 src/main.cpp | 27 +++++++--------------------
 1 file changed, 7 insertions(+), 20 deletions(-)

diff --git a/src/main.cpp b/src/main.cpp
index 319a2be..86a1c87 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -11,8 +11,6 @@
 
 #define POWER_SUPPLY_CHECK_PIN 13
 
-#define SELF_DRIVE_INTERVAL 100
-
 const uint8_t group_pins[KEY_GROUP_NUM] {14, 15, 16, 17, 18, 19, 20, 21, 22};
 
 // not KEY0%6..not KEY5%6
@@ -21,8 +19,7 @@ const uint8_t key_pins[KEY_PINS] {2, 3, 4, 5, 6, 7};
 uint8_t keys_pressed[NUMBER_OF_KEYS];
 // K1, K2, K3, K4, K5, K12, K13, K14, K15
 const uint8_t self_drive_pins[KEY_GROUP_NUM] {8, 9, 10, 11, 12, 26, 23, 24, 25};
-volatile uint8_t current_self_drive_pin = 0;
-IntervalTimer self_drive_timer = IntervalTimer();
+uint8_t current_self_drive_pin = 0;
 
 // Map the current array and pressed key to a MIDI note
 uint8_t mapToMidi(uint8_t active_key_group, uint8_t key) {
@@ -76,23 +73,12 @@ int8_t getActiveKeyGroup() {
 // Set the next self drive pin
 FASTRUN void nextSelfDrivePin() {
   // Set the current pin to high
+  digitalWriteFast(self_drive_pins[current_self_drive_pin!=0?current_self_drive_pin-1:KEY_GROUP_NUM-1], LOW);
   digitalWriteFast(self_drive_pins[current_self_drive_pin], HIGH);
   // Set the next pin
   current_self_drive_pin = (current_self_drive_pin + 1) % KEY_GROUP_NUM;
 }
 
-// Interrupt for power supply check
-FASTRUN void powerStateChanged() {
-  uint8_t state = digitalReadFast(POWER_SUPPLY_CHECK_PIN);
-  // ! inverted
-  if (state == LOW) {
-    current_self_drive_pin = 0;
-    self_drive_timer.begin(nextSelfDrivePin, SELF_DRIVE_INTERVAL);
-  } else {
-    self_drive_timer.end();
-  }
-}
-
 // Initial start function
 void setup() {
   // Set all in- and outputs
@@ -104,10 +90,6 @@ void setup() {
     pinMode(key_pins[i], INPUT);
   }
   pinMode(POWER_SUPPLY_CHECK_PIN, INPUT);
-  // Manual call, so we can set the initial state
-  powerStateChanged();
-  // Setup interrupt for power supply
-  attachInterrupt(POWER_SUPPLY_CHECK_PIN, []() { while (true); }, CHANGE);
 }
 
 // Main loop
@@ -153,4 +135,9 @@ void loop() {
   // MIDI Controllers should discard incoming MIDI messages.
   while (usbMIDI.read()) {
   }
+
+  // switch to next key group, if self powered
+  if (digitalReadFast(POWER_SUPPLY_CHECK_PIN) == LOW) {
+    nextSelfDrivePin();
+  }
 }
\ No newline at end of file