Several fixes.

MIDI-Host-Adapter.ino

@@ -31,13 +31,13 @@
 #define MIDI_CH_BIT1 3
 #define MIDI_CH_BIT0 2
 
-bool swap_nibbles = false;
+bool swap_nibbles = true;
 bool high_freq = false;
 
 #define BRIGHTNESS 6
 #define INITIAL_MIDI_CHANNEL 1
-#define BUTTON_DEBOUNCE_TIME_MS 50
-#define BUTTON_DOUBLE_PRESS_MS 200
+#define BUTTON_DEBOUNCE_TIME_MS 150
+#define BUTTON_DOUBLE_PRESS_MS 250
 #define BLINK_FREQUENCY_MS 500
 #define EEPROM_ADDRESS 0x42
 
@@ -47,6 +47,7 @@ elapsedMillis button_debounce_timer;
 elapsedMillis blink_timer;
 elapsedMillis double_press_timer;
 uint8_t actual_channel;
+uint8_t new_channel;
 
 void setup() {
   Serial.begin(9600);
@@ -67,6 +68,7 @@ void setup() {
     Serial.print("Reading channel from EEPROM: ");
     Serial.println(actual_channel, DEC);
   }
+  new_channel = actual_channel;
 
   pinMode(MIDI_CH_BIT3, OUTPUT);
   pinMode(MIDI_CH_BIT2, OUTPUT);
@@ -84,7 +86,6 @@ void setup() {
 
 void loop() {
   uint8_t button;
-  static uint8_t new_channel;
 
   button = tm.ReadKey16();
 
@@ -93,6 +94,7 @@ void loop() {
     Serial.print("Button once: ");
     Serial.println(button, DEC);
     button_debounce_timer = 0;
+    double_press_timer = 0;
     blink_timer = 0;
     new_channel = button;
     tm.DisplayDecNumNibble(new_channel, actual_channel, 0, false, TMAlignTextRight);
@@ -101,16 +103,17 @@ void loop() {
     Serial.print("Button twice: ");
     Serial.println(button, DEC);
     actual_channel = new_channel;
-    EEPROM.update(EEPROM_ADDRESS, 0xf0 & actual_channel);
+    EEPROM.update(EEPROM_ADDRESS, 0xf0 | actual_channel);
     SetMidiChannel(actual_channel);
-    double_press_timer = 0;
-  } else if (actual_channel != new_channel)
+  } else if (actual_channel != new_channel) {
     if (blink_timer > BLINK_FREQUENCY_MS) {
       blink_timer = 0;
       tm.DisplayDecNum(actual_channel, 0, false, TMAlignTextRight);
     } else if (blink_timer > BLINK_FREQUENCY_MS / 2) {
       tm.DisplayDecNumNibble(new_channel, actual_channel, 0, false, TMAlignTextRight);
     }
+  } else
+    tm.DisplayDecNum(actual_channel, 0, false, TMAlignTextRight);
 }
 
 void SetMidiChannel(uint8_t channel) {
@@ -133,8 +136,7 @@ void SetMidiChannel(uint8_t channel) {
 }
 
 void printBinary(uint32_t value, uint8_t len) {
-  for (len; len >= 0; len--) {
-    Serial.print((char)('0' + ((value >> len) & 1)));
+  for (uint8_t b = len; b > 0; --b) {
+    Serial.print((char)('0' + ((value >> (b - 1)) & 1)));
   }
-  Serial.println();
 }