diff --git a/sound-driver/Makefile b/sound-driver/Makefile
index fa14a2a..f6d592d 100644
--- a/sound-driver/Makefile
+++ b/sound-driver/Makefile
@@ -4,21 +4,22 @@ OBJDUMP=$(TOOLCHAIN_PREFIX)/bin/msp430-elf-objdump
 
 ARTIFACT=firmware
 MCU=msp430g2553
-COMMONFLAGS=-Wall -mmcu=$(MCU) -I $(TOOLCHAIN_PREFIX)/include -O0 -g0
-CFLAGS=$(COMMONFLAGS) -std=gnu99 
-ASFLAGS=$(COMMONFLAGS) -D__ASSEMBLER__
+COMMONFLAGS=-Wall -mmcu=$(MCU) -I $(TOOLCHAIN_PREFIX)/include -g0 -fdata-sections -ffunction-sections
 
-# for debugging
-CFLAGS+= -g3 -ggdb -gdwarf-2
+DEBUGFLAGS=
+# DEBUGFLAGS+= -g3 -ggdb -gdwarf-2
 
-LDFLAGS=-mmcu=$(MCU) -L $(TOOLCHAIN_PREFIX)/include
+CFLAGS=$(COMMONFLAGS) -std=gnu99 -O0 $(DEBUGFLAGS)
+ASFLAGS=$(COMMONFLAGS) -D__ASSEMBLER__ -Os $(DEBUGFLAGS)
+
+LDFLAGS=-mmcu=$(MCU) -L $(TOOLCHAIN_PREFIX)/include -Wl,-Map,firmware.map
 
 $(ARTIFACT).elf:	main.o scheduler.o spi.o spi_init.o sequencer.o melody_tetris.o melody_tusch1.o psg.o mute.o melody_pling.o
 	$(CC) -o $@ $(LDFLAGS) $^
 	$(OBJDUMP) -D $(ARTIFACT).elf > $(ARTIFACT).txt
 
 .c.o:	
-	$(CC) $(CFLAGS) -c $<
+	$(CC) $(CFLAGS) -c $< 
 
 .S.o:	
 	$(CC) $(ASFLAGS) -c $<
diff --git a/sound-driver/main.c b/sound-driver/main.c
index 8e4a119..84ea662 100644
--- a/sound-driver/main.c
+++ b/sound-driver/main.c
@@ -6,8 +6,6 @@
 #include "psg.h"
 #include "scheduler.h"
 #include "sequencer.h"
-#include "melody_tetris.h"
-#include "melody_tusch1.h"
 #include "mute.h"
 
 int main() {
@@ -31,8 +29,6 @@ int main() {
 
   __enable_interrupt();
 
-  // playMelodyTetris();
-
   while (1) {
     schExec();
   }
diff --git a/sound-driver/melody_pling.c b/sound-driver/melody_pling.c
index 6b76b56..5854074 100644
--- a/sound-driver/melody_pling.c
+++ b/sound-driver/melody_pling.c
@@ -15,7 +15,8 @@ const t_tone plingVoice1[] = {
 };
 
 t_melodies pling = {
-  .melodies = { { .chip = 1, .amplitude = 12, .tones = plingVoice1 } },
+  .melodies = { { .amplitude = 12, .tones = plingVoice1 } },
+  .chip = 1,
   .numOfMelodies = 1,
   .pace = 200,
   .slotMask = 0x02
diff --git a/sound-driver/melody_tetris.c b/sound-driver/melody_tetris.c
index 30091fb..9dc2db3 100644
--- a/sound-driver/melody_tetris.c
+++ b/sound-driver/melody_tetris.c
@@ -923,7 +923,8 @@ const t_tone voice3[] = {
 };
 
 t_melodies tetrisTheme = {
-  .melodies = { { .chip = 0, .amplitude = 8, .tones = voice1 }, { .chip = 0, .amplitude = 8, .tones = voice2 }, { .chip = 0, .amplitude = 8, .tones = voice3 } },
+  .melodies = { { .amplitude = 8, .tones = voice1 }, { .amplitude = 8, .tones = voice2 }, { .amplitude = 8, .tones = voice3 } },
+  .chip = 0,
   .numOfMelodies = 3,
   .pace = 160,
   .slotMask = 0x01
diff --git a/sound-driver/melody_tusch1.c b/sound-driver/melody_tusch1.c
index a596ab2..ae4cfde 100644
--- a/sound-driver/melody_tusch1.c
+++ b/sound-driver/melody_tusch1.c
@@ -72,7 +72,8 @@ const t_tone tusch1voice3[] = {
 };
 
 t_melodies tusch1 = {
-  .melodies = { { .chip = 1, .amplitude = 12, .tones = tusch1voice1 }, { .chip = 1, .amplitude = 12, .tones = tusch1voice2 }, { .chip = 1, .amplitude = 12, .tones = tusch1voice3 } },
+  .melodies = { { .amplitude = 12, .tones = tusch1voice1 }, { .amplitude = 12, .tones = tusch1voice2 }, { .amplitude = 12, .tones = tusch1voice3 } },
+  .chip = 1,
   .numOfMelodies = 3,
   .pace = 200,
   .slotMask = 0x02
@@ -80,7 +81,6 @@ t_melodies tusch1 = {
 
 void playTusch1() {
   sequencerPlayMelodies(&tusch1);
-  playMelodyTetrisFaster();
 }
 
 
diff --git a/sound-driver/psg.c b/sound-driver/psg.c
index b00dd6a..c4222a4 100644
--- a/sound-driver/psg.c
+++ b/sound-driver/psg.c
@@ -175,5 +175,21 @@ void psgInit() {
   // disable everything
   psgWrite(0, _ENABLE_REG, 0xff);
   psgWrite(1, _ENABLE_REG, 0xff);
+
+  // volume to 0 on all channels
+  psgWrite(0, CHANNEL_A_AMPLITUDE_REG, 0);
+  psgWrite(0, CHANNEL_B_AMPLITUDE_REG, 0);
+  psgWrite(0, CHANNEL_C_AMPLITUDE_REG, 0);
+  psgWrite(1, CHANNEL_A_AMPLITUDE_REG, 0);
+  psgWrite(1, CHANNEL_B_AMPLITUDE_REG, 0);
+  psgWrite(1, CHANNEL_C_AMPLITUDE_REG, 0);
+
+  // frequency preset
+  psgWriteFrequency(0, 0, 0);
+  psgWriteFrequency(0, 1, 0);
+  psgWriteFrequency(0, 2, 0);
+  psgWriteFrequency(1, 0, 0);
+  psgWriteFrequency(1, 1, 0);
+  psgWriteFrequency(1, 2, 0);
 }
 
diff --git a/sound-driver/sequencer.c b/sound-driver/sequencer.c
index 9ffc25c..a443482 100644
--- a/sound-driver/sequencer.c
+++ b/sound-driver/sequencer.c
@@ -59,7 +59,7 @@ void sequencerExec(void *handle) {
           if (melody->tones[melody->idx].length == e_L_EndMark) {
             melody->idx = 0;
           }
-          psgPlayTone(melody->chip, channel, melody->amplitude, melody->tones[melody->idx].octave, melody->tones[melody->idx].note);
+          psgPlayTone(melodies->chip, channel, melody->amplitude, melody->tones[melody->idx].octave, melody->tones[melody->idx].note);
           melody->lengthCnt = (melody->tones[melody->idx].staccato) ? 
             (calcLength(melodies, melody->tones[melody->idx].length) / 2) : 
             calcLength(melodies, melody->tones[melody->idx].length);
@@ -78,7 +78,7 @@ void sequencerExec(void *handle) {
         }
         break;
       case e_StaccatoBreak:
-        psgPlayTone(melody->chip, channel, 0, e_O_Null, e_Pause);
+        psgPlayTone(melodies->chip, channel, 0, e_O_Null, e_Pause);
         melody->lengthCnt = calcLength(melodies, melody->tones[melody->idx].length) / 2;
         melody->state = e_HoldStaccatoBreak;
         break;
@@ -90,7 +90,7 @@ void sequencerExec(void *handle) {
         break;
       case e_SeparateTone:
         if (! (melody->tones[melody->idx].legato)) {
-          psgPlayTone(melody->chip, channel, 0, e_O_Null, e_Pause);
+          psgPlayTone(melodies->chip, channel, 0, e_O_Null, e_Pause);
         }
         melody->idx += 1;
         melody->state = e_PlayTone;
diff --git a/sound-driver/sequencer.h b/sound-driver/sequencer.h
index bdb4fd6..3488bbf 100644
--- a/sound-driver/sequencer.h
+++ b/sound-driver/sequencer.h
@@ -42,7 +42,6 @@ typedef enum {
 
 typedef struct {
   uint16_t idx;
-  uint8_t chip;
   uint16_t lengthCnt;
   t_sequencerState state;
   uint8_t amplitude;
@@ -52,11 +51,12 @@ typedef struct {
 #define SEQUENCER_PERIOD 4 // ms
 #define NUM_OF_CHANNELS 3
 typedef struct {
+  uint8_t chip;
   uint8_t slotMask;
   uint8_t taskId;
   uint16_t quarterLength;
   uint8_t numOfMelodies;
-  uint8_t pace; // quarter notes per minute
+  uint16_t pace; // quarter notes per minute
   uint8_t sync;
   t_melody melodies[NUM_OF_CHANNELS];
 } t_melodies;
diff --git a/sound-driver/spi.S b/sound-driver/spi.S
index c8d4864..5fcdede 100644
--- a/sound-driver/spi.S
+++ b/sound-driver/spi.S
@@ -1,10 +1,10 @@
 #include <msp430g2553.h>
 #include "soundCodes.h"
 
-  .section ".data"
-  .global cmd
-cmd:
-  .byte   
+;;  .global cmd
+;;  .section .data.spi,"aw"
+;;cmd:
+;;  .byte   
 
   .section ".text","ax",@progbits
 receive_isr:
@@ -29,17 +29,19 @@ spiCmdHandler_2:
 spiCmdHandler_3:
   bit     #SOUND_START, &cmd
   jz      spiCmdHandler_4
-  call    #playMelodyTetris
+  ;;call    #playMelodyTetris
   bic     #SOUND_START, &cmd
 spiCmdHandler_4:
   bit     #SOUND_GAMEOVER, &cmd
   jz      spiCmdHandler_5
+  ;;call    #stopMelodyTetris
   ;; insert a call here
   bic     #SOUND_GAMEOVER, &cmd
 spiCmdHandler_5:
   bit     #SOUND_FANFARE, &cmd
   jz      spiCmdHandler_6
-  call    #playTusch1
+  ;;call    #playMelodyTetrisFaster
+  ;;call    #playTusch1
   bic     #SOUND_FANFARE, &cmd
 spiCmdHandler_6:
   bit     #SOUND_LOCK, &cmd
@@ -54,17 +56,12 @@ spiCmdHandler_7:
 spiCmdHandler_8:
   bit     #SOUND_PLING, &cmd
   jz      spiCmdHandler_end
-  call    #playPling
+  ;;call    #playPling
   bic     #SOUND_PLING, &cmd
 spiCmdHandler_end:
   ret
 
- 
-
-
-
   .section "__interrupt_vector_8","ax",@progbits
   .word   receive_isr
 
-
   .end
diff --git a/sound-driver/spi_init.c b/sound-driver/spi_init.c
index 5d831b1..fdef72c 100644
--- a/sound-driver/spi_init.c
+++ b/sound-driver/spi_init.c
@@ -6,7 +6,7 @@
 #include "soundCodes.h"
 
 
-extern uint8_t cmd;
+uint8_t cmd;
 
 void spiInit() {
   // SPI slave