Small fixes.

MIDI-Host-Adapter.ino

@@ -1,6 +1,27 @@
+/*
+   MIDI-Host-Adapter
+
+   (c)2023 H. Wirtz <wirtz@parasitstudio.de>
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
+*/
+
 #include <TM1638plus_Model2.h>
 #include <elapsedMillis.h>
 #include <limits.h>
+#include <EEPROM.h>
 
 #define STROBE_TM 9
 #define CLOCK_TM 8
@@ -18,16 +39,18 @@ bool high_freq = false;
 #define BUTTON_DEBOUNCE_TIME_MS 50
 #define BUTTON_DOUBLE_PRESS_MS 200
 #define BLINK_FREQUENCY_MS 500
+#define EEPROM_ADDRESS 0x42
 
 // Constructor object
 TM1638plus_Model2 tm(STROBE_TM, CLOCK_TM, DIO_TM, swap_nibbles, high_freq);
 elapsedMillis button_debounce_timer;
 elapsedMillis blink_timer;
 elapsedMillis double_press_timer;
+uint8_t actual_channel;
 
 void setup() {
   Serial.begin(9600);
-  delay(100);
+  delay(50);
 
   Serial.println("<SETUP>");
 
@@ -35,6 +58,16 @@ void setup() {
   tm.brightness(BRIGHTNESS);
   tm.DisplayStr("MIDIHOST", 0);
 
+  uint8_t tmp_channel = EEPROM.read(EEPROM_ADDRESS);
+  if (tmp_channel & 0xf0 != 0xf0) {
+    actual_channel = 1;
+    Serial.println("Setting channel to 1");
+  } else {
+    actual_channel = 0x0f & tmp_channel;
+    Serial.print("Reading channel from EEPROM: ");
+    Serial.println(actual_channel, DEC);
+  }
+
   pinMode(MIDI_CH_BIT3, OUTPUT);
   pinMode(MIDI_CH_BIT2, OUTPUT);
   pinMode(MIDI_CH_BIT1, OUTPUT);
@@ -44,19 +77,15 @@ void setup() {
 
   delay(500);
 
+  tm.DisplayDecNum(actual_channel, 0, false, TMAlignTextRight);
+
   Serial.println("</SETUP>");
 }
 
 void loop() {
   uint8_t button;
-  static uint8_t actual_channel;
   static uint8_t new_channel;
 
-  if (actual_channel == 0) {
-    actual_channel = 1;
-    tm.DisplayDecNum(actual_channel, 0, false, TMAlignTextRight);
-  }
-
   button = tm.ReadKey16();
 
   if (button > 0 && button_debounce_timer > BUTTON_DEBOUNCE_TIME_MS && double_press_timer > BUTTON_DOUBLE_PRESS_MS) {
@@ -72,6 +101,7 @@ void loop() {
     Serial.print("Button twice: ");
     Serial.println(button, DEC);
     actual_channel = new_channel;
+    EEPROM.update(EEPROM_ADDRESS, 0xf0 & actual_channel);
     SetMidiChannel(actual_channel);
     double_press_timer = 0;
   } else if (actual_channel != new_channel)
@@ -84,7 +114,12 @@ void loop() {
 }
 
 void SetMidiChannel(uint8_t channel) {
-  Serial.print("Setting MIDI channel: ");
+  if (channel < 1 || channel > 16) {
+    Serial.print("ERROR: MIDI channel number out of range: ");
+    Serial.print(channel, DEC);
+    return;
+  }
+  Serial.print("Setting MIDI channel to: ");
   Serial.print(channel, DEC);
   channel--;
   Serial.print(" (");