FM-Radio mit Arduino Pro Mini und Si4703 - Programm hängt sich auf!

[HaWe]

ich finde bare-metal-C-Tipps zu Arduino C++ Klassen wie Wire auch nicht so hilfreich, denn gerade die Wire Class ist bereits hoch optimiert.
Eventuell reicht es, wenn du ab und zu einfach mal deine i2c-Devices "anpingst" , um zu sehen, ob ein Fehler zurückgegeben wird, und danach erst (wenn kein Fehler) deine Device-Lese-Schreib-Funktionen aufrufst:

Wire.beginTransmission(addr); // transmit to device I2C addr
int ioerr=Wire.endTransmission();
if(ioerr) {   // Ausgabe eines Fehlers samt i2c-addr. 
  Serial.print("Fehler bei addr 0x"); 
  if (addr<16) { Serial.print("0"); }
  Serial.print(addr,HEX); 
  Serial.print(" ioerr=");  
  Serial.println(ioerr); 
}

So kannst du checken, wie oft hier überhaupt wo was schief läuft.

Aber mal eine ganz andere Frage :
Wo in deinem Sketch (void setup() ) startest du denn überhaupt Wire mit Wire.begin() - irgendwie sehe ich es nicht....?

/**************************************************************************
 * This code is a modification/extract of several example-codes that come *
 * with different si4703-libraries. Libraries used are fetched from:      *
 *         http://www.mathertel.de/Arduino/RadioLibrary.aspx              *
 * Not sure if other libraries work with same code.                       *
 * 5 push-buttons control the radio (see comments in code)                *
 * OLED-display shows 3 lines:                                            *
 *  1- "frequency"                                                        *
 *  2- "station name" or "scan mode"                                      *
 *  3- "volume level" + "battery voltage" or "CHARGE BATTERY"             *
 * Code for voltage monitoring is fetched from:                           *
 * https://code.google.com/archive/p/ti...Voltmeter.wiki  *
 *                                                                        *
 * U.Galepp Jan./2018                                                     *
 **************************************************************************/

#include <Arduino.h>
#include <Wire.h>
#include <radio.h>
#include <si4703.h>
#include "U8glib.h"

U8GLIB_SSD1306_128X64 u8g(U8G_I2C_OPT_NONE);  // define type of display (OLED 0.96" 128x64 pix)

#define FIX_BAND     RADIO_BAND_FM            // the band that will be tuned by this sketch is FM
#define FIX_STATION  8760                     // station at start-up is 87.60 MHz
#define FIX_VOLUME   1                        // volume level at start-up

SI4703 radio;                                 // Create an instance of Class for Si4703 Chip

int volume = FIX_VOLUME;
int button_1 = 3;                             // button volume up at Pin 3
int button_2 = 4;                             // button volume down at Pin 4
int button_3 = 5;                             // button station swap at Pin 5
int button_4 = 6;                             // button scan up at Pin 6
int button_5 = 7;                             // button scan down at Pin 7
int buttonState_1 = 0;
int buttonState_2 = 0;
int buttonState_3 = 0;
int buttonState_4 = 0;
int buttonState_5 = 0;
int flag = 0;                                 // used for decission to show "Station Name" or "scan mode"
int stationNr = 0;
int fmFreq[10] = {8760, 8820, 9100, 9350, 9500, 10030, 10080, 10280, 10330, 10480};
char* fmName[10] = {"   NDR 1 MV", "   NDR Kultur", "   NDR 1 MV", "   NDR 2 MV", 
                   "     N-JOY", "Deutschlandfunk", "  Antenne MV", "   NDR Info", 
                    "Radio Paradiso", "  Ostseewelle"};
char vol[2];
float volts;
char akku[4];

long readVcc() {
  long result;
                                             // Read 1.1V reference against AVcc
  ADMUX = _BV(REFS0) | _BV(MUX3) 
              | _BV(MUX2) | _BV(MUX1);
  delay(2);                                  // Wait for Vref to settle
  ADCSRA |= _BV(ADSC);                       // Convert
  while (bit_is_set(ADCSRA,ADSC));
  result = ADCL;
  result |= ADCH<<8;
  result = 1126400L / result;                // Back-calculate AVcc in mV
  return result;
}

/******************************
 *           Setup            *
 *****************************/
void setup() {

  radio.init();                               // initialize radio 
  
  radio.setBandFrequency(FIX_BAND, FIX_STATION);
  radio.setVolume(volume);
  radio.setMono(false);
  radio.setMute(false);

  pinMode(button_1, INPUT);                   // define button Pins
  pinMode(button_2, INPUT);                   // -||-
  pinMode(button_3, INPUT);                   // -||-
  pinMode(button_4, INPUT);                   // -||-
  pinMode(button_5, INPUT);                   // -||-
  digitalWrite(button_1, HIGH);               // button-Pin Pull-up
  digitalWrite(button_2, HIGH);               // -||-
  digitalWrite(button_3, HIGH);               // -||-
  digitalWrite(button_4, HIGH);               // -||-
  digitalWrite(button_5, HIGH);               // -||-
} 

/******************************
 * Subroutine Display on OLED *
 *****************************/
void displayData()                           
  {
  volts = (float)readVcc()/(float)1000;       // read Vcc and divide by 1000
    
  char s[12];
  radio.formatFrequency(s, sizeof(s));        // format frequency value to output like: "87,60 MHz"

    u8g.firstPage(); 
    do {
    u8g.drawFrame(0,0,128,64);                // display frame around screen
    u8g.setFont(u8g_font_timB14);
    u8g.drawStr(15, 22, s);
    u8g.setFont(u8g_font_unifont);
    if(flag==0)
      {
      u8g.drawStr(4, 44, fmName[stationNr]);  // if fequency from array, take name from array too
      }
    if(flag==1)
     {
      u8g.drawStr(25, 44, "scan mode");       // if frequency from scan, show "scan mode"
     }

    if(volts > 3.3)                           // if Vcc > 3.3V display "Volume" & "Volt"       
        {
        u8g.setFont(u8g_font_6x13);
        u8g.drawStr(6, 59,"Volume: ");                          
        sprintf (vol, "%d", volume);          // change int "volume" to char "vol"                 
        u8g.drawStr(50, 59, vol);
        u8g.drawStr(68, 59,"Bat:");
        dtostrf(volts, 2, 1, akku);           // change float "volts" to char "akku"  
        u8g.drawStr(94, 59,akku);
        u8g.drawStr(115, 59,"V");
        }
       else                                   // if VCC >= 3.3V display "CHARGE BATTERY"
       {
        u8g.drawStr(6, 59,"CHARGE BATTERY");
       }
      } 
     while( u8g.nextPage() );
  }

/******************************
 *         Main Loop          *
 *****************************/
void loop() 
  {
  buttonState_1 = digitalRead(button_1);
  buttonState_2 = digitalRead(button_2);
  buttonState_3 = digitalRead(button_3);
  buttonState_4 = digitalRead(button_4);
  buttonState_5 = digitalRead(button_5);
  
  if (buttonState_1 == LOW) 
    {
      volume ++;
      if (volume == 16) volume = 15;
      radio.setVolume(volume);
      delay(100);
     } 
     
  else if (buttonState_2 == LOW) 
    {
      volume --;
      if (volume < 0) volume = 0;
      radio.setVolume(volume);
      delay(100);
      } 
      
  else if (buttonState_3 == LOW)
    {
      stationNr ++;
      if (stationNr == 10) stationNr = 0;
      radio.setFrequency(fmFreq[stationNr]);
      flag = 0;
      delay(500);
      }
      
  else if (buttonState_4 == LOW)
    {
      radio.seekUp();
      flag = 1;
      delay(500);
      }

  else if (buttonState_5 == LOW)
    {
      radio.seekDown();
      flag = 1;
      delay(500);
      }   
  else displayData();
 }