diff --git a/arduino/SN76489-test/SN76489-test.ino b/arduino/SN76489-test/SN76489-test.ino
index afdd351..bffcee4 100644
--- a/arduino/SN76489-test/SN76489-test.ino
+++ b/arduino/SN76489-test/SN76489-test.ino
@@ -1,24 +1,97 @@
 /**
  * SN76489 sound chip test
- * 
- * DATA BUS IS: 3, 4, 5, 6, 7, 8, 9, 10 (NOTE: 3 is D0, but D0 is the MSB)
- * WE 11   (Active low)
+ *
+ * DATA BUS IS: 2, 3, 4, 5, 6, 7, 8, 9 (NOTE: 2 is D0, but D0 is the MSB)
+ * WE 10   (Active low)
  */
 
+const byte DATA_BUS[] = {9, 8, 7, 6, 5, 4, 3, 2};
+const byte WE = 10;
+
 void setup() {
-    DDRD = DDRD | B11111000; // Port D (arduino pins 3 to 7) is output. In or to preserve serial pins and interrupt pin
-    DDRB = B00001111; // Port B (0,1,2,3) = pins 8,9,10,11 output (11 is WE)
+  // Setup pins
+  for(int pin=0; pin < 8; pin++) {
+    pinMode(DATA_BUS[pin], OUTPUT);
+  }
+  pinMode(WE, OUTPUT);
+  digitalWrite(WE, HIGH);
+
+  /*  Init device (silence all channels)  
+   *  Bits meaning:
+   *  1 R0 R1 R2 A0 A1 A2 A3
+   *    Bit0 is 1
+   *    Bit1,2,3 select the channel: 001, 011, 101, 111(noise)
+   *    Bit4,5,6,7 selecy the attenuation (0000=full volume, 1111=silent)
+   */
+  SendByte(B10011111);    // Sil ch 1
+  SendByte(B10111111);    // Sil ch 2
+  SendByte(B11011111);    // Sil ch 3
+  SendByte(B11111111);    // Sil noise
+
+  delay(1000);
+
+  // Channel 1 to max volume
+  SendByte(B10010000);
+  
+  /*  Play note on channel 1
+   *  Requires sending 2 bytes.
+   *  Bits meaning:
+   *  1 R0 R1 R2 F6 F7 F8 F9    0 0 F0 F1 F2 F3 F4 F5
+   *    First bit:  1=low byte (first sent), 0=high byte (last sent)
+   *    R0,1,2: select the channel: 000, 010, 100, 110(noise)
+   *    F0..9: frequency value calculated as:
+   *      f = REF_CLK / 32 * n
+   *      Where f is the resulting frequency in HZ, REF_CLK is the reference clock on pin 14 in HZ and n is F0..9
+   */
+   SendByte(B10000000); SendByte(B00100000);
+   delay(500);
+   SendByte(B10000000); SendByte(B00010000);
+   delay(500);
+   SendByte(B10000000); SendByte(B00001000);
+   delay(500);
+
+   SendByte(B10011111);    // Sil ch 1 
+
+   delay(1000);
+
+   // Play notes on channel 1,2,3
+   SendByte(B10010000); // Channel 1 vol max (0000)
+   SendByte(B10000000); SendByte(B00100000);  // Note on ch1
+   delay(500);
+   SendByte(B10110010); // Channel 2 vol 0010
+   SendByte(B10100000); SendByte(B00010000);  // Note on ch2
+   delay(500);
+   SendByte(B11010100); // Channel 3 vol 0100
+   SendByte(B11000000); SendByte(B00001000);  // Note on ch3
+   delay(500);
+
+   SendByte(B10011111);    // Sil ch 1 
+   SendByte(B10111111);    // Sil ch 2
+   SendByte(B11011111);    // Sil ch 3
+
+   delay(1000);
+   /*
+    * Play noise on channel 4
+    */
+  
+  
 }
 
 void loop() {
+  
 }
 
-
-
-void writeByte(byte b) {
-    // Split byte to two parts and write to data bus
-    PORTD = b << 3;
-    PORTB = b >> 5;
-    // Pulse WE
-    b
+void SendByte(byte b) {
+  digitalWrite(DATA_BUS[0], (b&1)?HIGH:LOW);
+  digitalWrite(DATA_BUS[1], (b&2)?HIGH:LOW);
+  digitalWrite(DATA_BUS[2], (b&4)?HIGH:LOW);
+  digitalWrite(DATA_BUS[3], (b&8)?HIGH:LOW);
+  digitalWrite(DATA_BUS[4], (b&16)?HIGH:LOW);
+  digitalWrite(DATA_BUS[5], (b&32)?HIGH:LOW);
+  digitalWrite(DATA_BUS[6], (b&64)?HIGH:LOW);
+  digitalWrite(DATA_BUS[7], (b&128)?HIGH:LOW);
+  delay(1);
+  digitalWrite(WE, LOW);
+  delay(1);
+  digitalWrite(WE, HIGH);
 }