diff --git a/STM32/libraries/BoardExamples/examples/Discovery407VG/STM32F4_Discovery_CS43L22_AudioCodecBasicTest/STM32F4_Discovery_CS43L22_AudioCodecBasicTest.ino b/STM32/libraries/BoardExamples/examples/Discovery407VG/STM32F4_Discovery_CS43L22_AudioCodecBasicTest/STM32F4_Discovery_CS43L22_AudioCodecBasicTest.ino
index 5e4bf78..f78cfa5 100644
--- a/STM32/libraries/BoardExamples/examples/Discovery407VG/STM32F4_Discovery_CS43L22_AudioCodecBasicTest/STM32F4_Discovery_CS43L22_AudioCodecBasicTest.ino
+++ b/STM32/libraries/BoardExamples/examples/Discovery407VG/STM32F4_Discovery_CS43L22_AudioCodecBasicTest/STM32F4_Discovery_CS43L22_AudioCodecBasicTest.ino
@@ -26,69 +26,33 @@ I2SClass I2S(SPI3, PC12 /*sd*/ , PA4 /*ws*/, PC10 /*ck*/, PC7/* MCK*/); // setup
 
 #define SERIALINTERFACE SerialUSB
 
-#define AUDIOCODEC_CHIP_SELECT PD4
+#define AUDIOCODEC_CS PD4
 
-#define CODEC_I2C_ADDR 0x4A // i2c address ( 2*0x4A = 0x94 )
+#define CODEC_ADDR 0x4A // i2c address ( 2*0x4A=0x94)
 
 void codec_writeReg(unsigned char reg, unsigned char data)
 {
-  Wire.beginTransmission(CODEC_I2C_ADDR);
+  uint8_t error;
+  Wire.beginTransmission(CODEC_ADDR);
   Wire.write(reg);
   Wire.write(data);
+  error = Wire.endTransmission();
 }
 
-enum CodecRegister {
-  ID                        = 1,
-  POWER_CTL1                = 2,
-  POWER_CTL2                = 4,
-  CLOCKING_CTL              = 5,
-  INTERFACE_CTL1            = 6,
-  INTERFACE_CTL2            = 7,
-  PASSTHROUGH_A             = 8,
-  PASSTHROUGH_B             = 9,
-  ANALOG_ZC_SR              = 0xa,
-  PASSTHROUGH_GANG_CTL      = 0xc,
-  PLAYBACK_CTL1             = 0xd,
-  MISC_CTL                  = 0xe,
-  PLAYBACK_CTL2             = 0xf,
-  PASSTHROUGH_A_VOL         = 0x14,
-  PASSTHROUGH_B_VOL         = 0x15,
-  PCMA_VOL                  = 0x1a,
-  PCMB_VOL                  = 0x1b,
-  BEEP_FREQ_ON_TIME         = 0x1c,
-  BEEP_VOL_OFF_TIME         = 0x1d,
-  BEEP_TONE_CFG             = 0x1e,
-  TONE_CTL                  = 0x1f,
-  MASTER_A_VOL              = 0x20,
-  MASTER_B_VOL              = 0x21,
-  HEADPHONE_A_VOL           = 0x22,
-  HEADPHONE_B_VOL           = 0x23,
-  SPEAKER_A_VOL             = 0x24,
-  SPEAKER_B_VOL             = 0x25,
-  CHANNEL_MIXER_AND_SWAP    = 0x26,
-  LIMIT_CTL1_THRESHOLDS     = 0x27,
-  LIMIT_CTL2_RELEASE_RATE   = 0x28,
-  LIMITER_ATTACK_RATE       = 0x29,
-  OVERFLOW_AND_CLOCK_STATUS = 0x2e,
-  BATTERY_COMPENSATION      = 0x2f,
-  VP_BATTERY_LEVEL          = 0x30,
-  SPEAKER_STATUS            = 0x31,
-  CHARGE_PUMP_FREQUENCY     = 0x34
-};
-
-
 // each register retries until success
 // if communication fails the device will hang
 // codec setup from
 // https://github.com/mubase/STM32F4-Arduino-core/blob/master/cores/maple/libmaple/stm32f4codec/codec.h
-// TBD: to be simplified and reworked
+// TBD: to be refactured
 
 void codec_reg_setup(void) 
 {
+  Wire.begin();
+  
   codec_writeReg(0x02, 0x01); // power save registers -> all on
   codec_writeReg(0x00, 0x99);
   codec_writeReg(0x47, 0x80); //inits
-  codec_writeReg(0x0d, 0x03); // playback ctrl
+  codec_writeReg(0xd, 0x3); // playback ctrl
   codec_writeReg(0x32, (1 << 7)); // vol
   codec_writeReg(0x32, (0 << 7)); // vol
   codec_writeReg(0x00, 0x00); // inits
@@ -101,24 +65,23 @@ void codec_reg_setup(void)
   codec_writeReg(0x80, 0x0a); // both channels on
   codec_writeReg(0x1f, 0x0f);
   codec_writeReg(0x02, 0x9e);
+
 }
 
 void setup()
 {
   pinMode(USER_BTN,      INPUT); //user button for sound stop, mandatory for STM MCUs if you want to use the button
-  pinMode(AUDIOCODEC_CHIP_SELECT, OUTPUT); // the chip select pin of the codec needs to be enabled 
+  pinMode(AUDIOCODEC_CS, OUTPUT); // the chip select pin of the codec needs to be enabled 
   
-  //digitalWrite(AUDIOCODEC_CHIP_SELECT, HIGH);
+  //digitalWrite(AUDIOCODEC_CS, HIGH);
   // start I2S
   // I2S will also produce MCK for the codec of aroung 12Mhz
   // without MCK the CS43L22 is not working
   I2S.begin(I2S_PHILIPS_MODE, 44000, 16);  
 
-  // MCK is running, enable codec
-  digitalWrite(AUDIOCODEC_CHIP_SELECT, HIGH); 
-
-  // start the I2C driver for codec register setup  
-  Wire.begin(); 
+  digitalWrite(AUDIOCODEC_CS, HIGH); // enable codec
+    
+  Wire.begin(); // start the I2C driver for codec register setup
   codec_reg_setup();
 
 }
@@ -128,9 +91,9 @@ void loop()
   static uint16_t n;
   I2S.write(n += 300); // produce sound: simple triangle waveform
 
-  if  ( digitalRead( USER_BTN ) ) // stop sound when user button pressed
+  if  ( digitalRead( USER_BTN ) ) 
   {
-    while (1) 
+    while (1) // stop sound when user button pressed
     {
 
     }
@@ -142,3 +105,4 @@ void loop()
 
 
 
+