76498 not working as expected

sound-driver/Makefile

@@ -7,11 +7,11 @@ MCU=msp430g2553
 CFLAGS=-Wall -mmcu=$(MCU) -std=gnu99 -I $(TOOLCHAIN_PREFIX)/include -O1 -g0
 
 # for debugging
-#CFLAGS+= -g3 -ggdb -gdwarf-2
+CFLAGS+= -g3 -ggdb -gdwarf-2
 
 LDFLAGS=-mmcu=$(MCU) -L $(TOOLCHAIN_PREFIX)/include
 
-$(ARTIFACT).elf:	main.o
+$(ARTIFACT).elf:	main.o scheduler.o spi.o sequencer.o melody.o ay_3_8913.o
 	$(CC) -o $@ $(LDFLAGS) $^
 	$(OBJDUMP) -D $(ARTIFACT).elf > $(ARTIFACT).txt
 

sound-driver/ay_3_8913.c

@@ -0,0 +1,190 @@
+#include <msp430g2553.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#include "psg.h"
+#include "scheduler.h"
+
+
+
+const uint16_t frequencyCodes[8][12] = {
+  //    C,   Cis,     D,   Dis,     E,     F,   Fis,     G,   Gis,     A,   Ais,     H
+  { 06535, 06234, 05747, 05474, 05233, 05002, 04563, 04353, 04153, 03762, 03600, 03424 },  // Octave 1
+  { 03256, 03116, 02764, 02636, 02515, 02401, 02271, 02165, 02065, 01771, 01700, 01612 },  // Octave 2
+  { 01527, 01447, 01372, 01317, 01247, 01201, 01135, 01073, 01033, 00774, 00740, 00705 },  // Octave 3
+  { 00654, 00624, 00575, 00550, 00523, 00500, 00456, 00435, 00415, 00376, 00360, 00342 },  // Octave 4
+  { 00326, 00312, 00276, 00264, 00252, 00240, 00227, 00217, 00207, 00177, 00170, 00161 },  // Octave 5
+  { 00153, 00145, 00137, 00132, 00125, 00120, 00114, 00107, 00103, 00100, 00074, 00071 },  // Octave 6
+  { 00065, 00062, 00060, 00055, 00052, 00050, 00046, 00044, 00042, 00040, 00036, 00034 },  // Octave 7
+  { 00033, 00031, 00030, 00026, 00025, 00024, 00023, 00022, 00021, 00020, 00017, 00016 }   // Octave 8
+};
+
+
+#define ADDR_DATA_REG P2OUT
+#define BUS_CTRL_REG P1OUT
+#define BC1 BIT3
+#define BDIR BIT1
+#define _CS0 BIT2
+#define _CS1 BIT0
+
+#define R0 0
+#define CHANNEL_A_TONE_PERIOD_FINE_REG R0
+#define R1 1
+#define CHANNEL_A_TONE_PERIOD_COARSE_REG R1
+#define R2 2
+#define CHANNEL_B_TONE_PERIOD_FINE_REG R2
+#define R3 3
+#define CHANNEL_B_TONE_PERIOD_COARSE_REG R3
+#define R4 4
+#define CHANNEL_C_TONE_PERIOD_FINE_REG R4
+#define R5 5
+#define CHANNEL_C_TONE_PERIOD_COARSE_REG R5
+#define R6 6
+#define NOISE_PERIOD_REG R6
+#define R7 7
+#define _ENABLE_REG R7
+#define R10 010
+#define CHANNEL_A_AMPLITUDE_REG R10
+#define R11 011
+#define CHANNEL_B_AMPLITUDE_REG R11
+#define R12 012
+#define CHANNEL_C_AMPLITUDE_REG R12
+#define R13 013
+#define ENVELOPE_PERIOD_FINE_REG R13
+#define R14 014
+#define ENVELOPE_PERIOD_COARSE_REG R13
+#define R15 015
+#define ENVELOPE_SHAPE_REG R15
+
+uint8_t psgShadowRegisters[14];
+
+inline static void BUS_OP_NACT() {
+  BUS_CTRL_REG &= ~(BDIR | BC1);
+}
+inline static void BUS_OP_INTAK() {
+  BUS_CTRL_REG |= BDIR | BC1;
+}
+inline static void BUS_OP_DWS() {
+  BUS_CTRL_REG |= BDIR;
+  BUS_CTRL_REG &= ~BC1;
+}
+inline static void BUS_OP_CS0_ENABLE() {
+  BUS_CTRL_REG &= ~_CS0;
+}
+inline static void BUS_OP_CS0_DISABLE() {
+  BUS_CTRL_REG |= _CS0;
+}
+inline static void BUS_OP_CS1_ENABLE() {
+  BUS_CTRL_REG &= ~_CS1;
+}
+inline static void BUS_OP_CS1_DISABLE() {
+  BUS_CTRL_REG |= _CS1;
+}
+
+#if 0
+static void delay() {
+asm volatile (
+    "push r12\n"
+    "mov.w #5, r12\n"
+    "loop:\n"
+    "dec.w r12\n"
+    "jnz loop\n"
+    "pop r12\n"
+);
+}
+#endif
+
+static uint8_t psgReadShadow(uint8_t address) {
+  return psgShadowRegisters[address];
+}
+
+static void psgWrite(uint8_t address, uint8_t data) {
+  psgShadowRegisters[address] = data;
+
+  // according to "State Timing" (p. 15) of datasheet
+
+  BUS_OP_CS1_ENABLE();
+
+  // put bus into inactive state
+  BUS_OP_NACT();
+
+  // put address on bus
+  ADDR_DATA_REG = address;
+
+  // address latch mode
+  BUS_OP_INTAK();
+
+  // latch address
+  BUS_OP_NACT();
+
+  // put data on bus
+  ADDR_DATA_REG = data;
+  
+  // set write to psg
+  BUS_OP_DWS();
+
+  // set inactive again
+  BUS_OP_NACT();
+
+  BUS_OP_CS1_DISABLE();
+}
+
+static void psgWriteFrequency(uint8_t channel, uint16_t frequencyCode) {
+  psgWrite(CHANNEL_A_TONE_PERIOD_FINE_REG + (channel * 2), (frequencyCode & 0x00ff));
+  psgWrite(CHANNEL_A_TONE_PERIOD_COARSE_REG + (channel * 2), ((frequencyCode >> 8) & 0x000f));
+}
+
+void psgPlayTone(uint8_t channel, uint8_t volume, t_octave octave, t_note note) {
+  if (note == e_Pause) {
+    psgWrite(_ENABLE_REG, psgReadShadow(_ENABLE_REG) | (1 << channel));
+  } else {
+    psgWrite(_ENABLE_REG, psgReadShadow(_ENABLE_REG) & ~(1 << channel));
+    psgAmplitude(channel, volume);
+    psgWriteFrequency(channel, frequencyCodes[octave][note]);
+  }
+}
+
+void psgAmplitude(uint8_t channel, uint8_t volume) {
+  psgWrite(CHANNEL_A_AMPLITUDE_REG + channel, volume);
+}
+
+void psgInit() {
+  // address/data bus
+  P2DIR = 0xff;
+  P2SEL = 0;
+  P2SEL2 = 0;
+
+  // sound chip reset
+  // BIT2: /RST
+  // P1DIR |= BIT2;
+
+#if 0
+  // put sound chip into reset state
+  P1OUT &= ~BIT2;
+  delay();
+  delay();
+  delay();
+#endif
+  
+  // bus control lines
+  // BIT3: BC1
+  // BIT1: BDIR
+  // BIT0: _CS1
+  // BIT2: _CS0
+  P1DIR |= BIT0 | BIT1 | BIT2 | BIT3 ;
+
+  // put bus into inactive state
+  BUS_CTRL_REG &= ~(BDIR | BC1);
+  
+#if 0
+  // release sound chip from reset state
+  P1OUT |= BIT2;
+  delay();
+  delay();
+  delay();
+#endif
+
+  // disable everything
+  psgWrite(_ENABLE_REG, 0xff);
+}
+

sound-driver/firmware.gdb

@@ -0,0 +1,2 @@
+target remote localhost:2000
+file firmware.elf

sound-driver/main.c

@@ -2,14 +2,11 @@
 #include <stdint.h>
 #include <stdlib.h>
 
-
+#include "spi.h"
-
+#include "psg.h"
-void __attribute__ ((interrupt (USCIAB0RX_VECTOR))) receive() {
+#include "scheduler.h"
-  if (UC0IFG & UCB0RXIFG) {
+#include "sequencer.h"
-    // receive an octet
+#include "melody.h"
-  }
-}
-
 
 int main() {
   WDTCTL = WDTPW | WDTHOLD;
@@ -22,22 +19,19 @@ int main() {
   BCSCTL2 = 0;
   BCSCTL3 = 0;
 
-  // SPI slave
-  // BIT4: UCB0STE
-  // BIT5: UCB0CLK
-  // BIT6: UCB0SOMI
-  // BIT7: UCB0SIMO
-  P1SEL |= BIT4 | BIT5 | BIT6 | BIT7;
-  P1SEL2 |= BIT4 | BIT5 | BIT6 | BIT7;
-  // most significant bit first, enable STE
-  UCB0CTL0 = UCSYNC | UCMSB | UCMODE_2;
-  UCB0CTL1 = 0x00;
-  // enable RX interrupt
-  UC0IE |= UCB0RXIE;
 
+  schInit();
+
+//  spiInit();
+  psgInit();
+  sequencerInit();
 
   __enable_interrupt();
 
+  melodyInit();
+
+
   while (1) {
+    schExec();
   }
 }

sound-driver/melody.h

@@ -0,0 +1,8 @@
+#ifndef _MELODY_H_
+#define _MELODY_H_
+
+
+void melodyInit();
+
+
+#endif // _MELODY_H_

sound-driver/psg.h

@@ -0,0 +1,46 @@
+#ifndef _PSG_H_
+#define _PSG_H_
+
+#include <stdint.h>
+
+typedef enum {
+  e_O_1 = 0,
+  e_O_2,
+  e_O_3,
+  e_O_4,
+  e_O_5,
+  e_O_6,
+  e_O_7,
+  e_O_8,
+  e_O_Null
+} t_octave;
+
+typedef enum {
+  e_C = 0,
+  e_Cis,
+  e_D,
+  e_Dis,
+  e_E,
+  e_F,
+  e_Fis,
+  e_G,
+  e_Gis,
+  e_A,
+  e_Ais,
+  e_H,
+  e_Pause,
+  e_Null
+} t_note;
+    
+#define e_Es e_Dis
+#define e_As e_Gis
+#define e_B e_Ais
+
+
+void psgInit();
+
+void psgPlayTone(uint8_t channel, uint8_t volume, t_octave octave, t_note note);
+void psgAmplitude(uint8_t channel, uint8_t volume);
+
+
+#endif // _PSG_H_

sound-driver/scheduler.c

@@ -0,0 +1,90 @@
+#include <stdlib.h>
+#include <msp430g2553.h>
+#include "scheduler.h"
+
+tTask tasks[MAX_NUM_OF_TASKS];
+
+
+void schInit() {
+  TACCR0 = 19600;
+  TACCTL0 = CCIE;
+  TACTL = MC_1 | ID_0 | TASSEL_2 | TACLR;
+
+  for (uint16_t i = 0; i < MAX_NUM_OF_TASKS; i++) {
+    tasks[i].delay = 0;
+    tasks[i].period = 0;
+    tasks[i].run = 0;
+    tasks[i].exec = NULL;
+    tasks[i].handle = NULL;
+  }
+}
+
+void __attribute__ ((interrupt (TIMER0_A0_VECTOR))) schUpdate() {
+  for (uint16_t i = 0; i < MAX_NUM_OF_TASKS; i++) {
+    if (tasks[i].exec != NULL) {
+      if (tasks[i].delay == 0) {
+        tasks[i].delay = tasks[i].period;
+        tasks[i].run++;
+      } else {
+        tasks[i].delay--;
+      }
+    }
+  }
+}
+
+uint16_t schAdd(void (*exec)(void *), void *handle, uint32_t delay, uint32_t period) {
+  uint16_t taskId = 0xffff;
+  for (uint16_t i = 0; i < MAX_NUM_OF_TASKS; i++) {
+    if (tasks[i].exec == NULL) {
+      tasks[i].delay = delay;
+      tasks[i].period = period;
+      if (delay == 0 && period == 0) {
+        tasks[i].run = 1;
+      } else {
+        tasks[i].run = 0;
+      }
+      tasks[i].exec = exec;
+      tasks[i].handle = handle;
+      taskId = i;
+      break;
+    }
+  }
+  return taskId;
+}
+
+/*
+void schDel(void (*exec)(void *), void *handle) {
+  for (uint16_t i = 0; i < MAX_NUM_OF_TASKS; i++) {
+    if ((tasks[i].exec == exec) && (tasks[i].handle == handle)) {
+      tasks[i].exec = NULL;
+      break;
+    }
+  }
+}
+*/
+void schDel(uint16_t taskId) {
+  tasks[taskId].exec = NULL;
+}
+
+void schExec() {
+  for (uint16_t i = 0; i < MAX_NUM_OF_TASKS; i++) {
+    // synchronize access to tasks[].run
+    __disable_interrupt(); 
+    if (tasks[i].exec != NULL && tasks[i].run > 0) {
+      tasks[i].run--;
+      // synchronize access to tasks[].run
+      // reenable interrupts before actually executing task
+      __enable_interrupt();
+      tasks[i].exec(tasks[i].handle);
+      if (tasks[i].period == 0) {
+        tasks[i].exec = NULL;
+      }
+    } else {
+      // synchronize access to tasks[].run
+      // reenable interrupts in case task is not yet executable
+      __enable_interrupt();
+    }
+  }
+}
+
+

sound-driver/scheduler.h

@@ -0,0 +1,28 @@
+#ifndef PONTCOOPSCHEDULER_H_
+#define PONTCOOPSCHEDULER_H_
+
+
+#include <stdint.h>
+
+
+
+#define MAX_NUM_OF_TASKS 8
+
+
+typedef struct {
+  uint16_t delay;
+  uint16_t period;
+  uint8_t run;
+  void (*exec)(void *handle);
+  void *handle;
+} tTask;
+
+
+void schInit();
+uint16_t schAdd(void (*exec)(void *), void *handle, uint32_t delay, uint32_t period);
+// void schDel(void (*exec)(void *), void *handle);
+void schDel(uint16_t taskId);
+void schExec();
+
+
+#endif /* PONTCOOPSCHEDULER_H_ */

sound-driver/sequencer.c

@@ -0,0 +1,99 @@
+#include <stdint.h>
+#include <stdbool.h>
+#include <sys/param.h>
+#include "sequencer.h"
+#include "scheduler.h"
+#include "psg.h"
+
+
+
+void sequencerInit() {
+}
+
+void sequencerExec(void *handle) {  
+  static uint16_t lengths[e_L_LengthEnd];
+  t_melodies *melodies = (t_melodies*) handle;
+
+  if (melodies->firstRun) {
+    melodies->firstRun = false;
+
+    lengths[e_L_1_4]  = 60000 / melodies->pace; // duration of a 1/4 tone in ms
+    lengths[e_L_1_2]  = lengths[e_L_1_4] << 1;
+    lengths[e_L_1]    = lengths[e_L_1_4] << 2;
+    lengths[e_L_1_8]  = lengths[e_L_1_4] >> 1;
+    lengths[e_L_1_16] = lengths[e_L_1_4] >> 2;
+    lengths[e_L_1_32] = lengths[e_L_1_4] >> 4;
+
+    for (uint8_t i = 0; i < e_L_LengthEnd; i++) {
+      lengths[i] /= SEQUENCER_PERIOD;
+    }
+  }
+
+  for (uint8_t channel = 0; channel < melodies->numOfMelodies; channel++) {
+    t_melody *melody = &(melodies->melodies[channel]);
+
+    switch (melody->state) {
+      case e_Init:
+        melody->state = e_PlayTone;
+        break;
+      case e_PlayTone:
+        if (melody->tones[melody->idx].length == e_L_SyncMark) {
+          if (melodies->sync == 0) {
+            melodies->sync = melodies->numOfMelodies;
+          }
+          melodies->sync -= 1;
+          melody->state = e_Sync;
+        } else {
+          if (melody->tones[melody->idx].length == e_L_EndMark) {
+            melody->idx = 0;
+          }
+          psgPlayTone(channel, melody->amplitude, melody->tones[melody->idx].octave, melody->tones[melody->idx].note);
+          melody->lengthCnt = (melody->tones[melody->idx].staccato) ? (lengths[melody->tones[melody->idx].length] / 2) : lengths[melody->tones[melody->idx].length];
+          melody->state = e_HoldTone;
+        }
+        break;
+      case e_Sync:
+        if (melodies->sync == 0) {
+          melody->state = e_SeparateTone;
+        }
+        break;
+      case e_HoldTone:
+        melody->lengthCnt -= 1;
+        if (melody->lengthCnt == 0) {
+          melody->state = (melody->tones[melody->idx].staccato) ? e_StaccatoBreak : e_SeparateTone;
+        }
+        break;
+      case e_StaccatoBreak:
+        psgPlayTone(channel, 0, e_O_Null, e_Pause);
+        melody->lengthCnt = lengths[melody->tones[melody->idx].length] / 2;
+        melody->state = e_HoldStaccatoBreak;
+        break;
+      case e_HoldStaccatoBreak:
+        melody->lengthCnt -= 1;
+        if (melody->lengthCnt == 0) {
+          melody->state = e_SeparateTone;
+        }
+        break;
+      case e_SeparateTone:
+        if (! (melody->tones[melody->idx].legato)) {
+          psgPlayTone(channel, 0, e_O_Null, e_Pause);
+        }
+        melody->idx += 1;
+        melody->state = e_PlayTone;
+        break;
+    }
+  }
+}
+
+uint16_t sequencerPlayMelodies(t_melodies *melodies) {
+  for (uint8_t i = 0; i < NUM_OF_CHANNELS; i++) {
+    melodies->melodies[i].idx = 0;
+    melodies->melodies[i].lengthCnt = 0;
+    melodies->melodies[i].state = e_Init;
+  }
+  melodies->sync = 0;
+  melodies->firstRun = true;
+
+  return schAdd(sequencerExec, (void*) melodies, 0, SEQUENCER_PERIOD);
+}
+

sound-driver/sequencer.h

@@ -0,0 +1,61 @@
+#ifndef _SEQUENCER_H_
+#define _SEQUENCER_H_
+
+
+#include <stdint.h>
+#include <stdbool.h>
+#include "psg.h"
+
+typedef enum {
+  e_L_1 = 0,
+  e_L_1_2 = 1,
+  e_L_1_4 = 2,
+  e_L_1_8 = 3,
+  e_L_1_16 = 4,
+  e_L_1_32 = 5,
+  e_L_LengthEnd = 6,
+  e_L_EndMark = 254,
+  e_L_SyncMark = 255,
+} t_noteLength;
+
+typedef struct {
+  t_octave octave;
+  t_note note;
+  t_noteLength length;
+  bool legato; 
+  bool staccato;
+} t_tone;
+
+typedef enum { 
+  e_Init,
+  e_PlayTone, 
+  e_Sync,
+  e_HoldTone, 
+  e_StaccatoBreak,
+  e_HoldStaccatoBreak,
+  e_SeparateTone 
+} t_sequencerState;
+
+typedef struct {
+  uint16_t idx;
+  uint16_t lengthCnt;
+  t_sequencerState state;
+  uint8_t amplitude;
+  const t_tone *tones;
+} t_melody;
+
+#define SEQUENCER_PERIOD 4 // ms
+#define NUM_OF_CHANNELS 3
+typedef struct {
+  uint8_t numOfMelodies;
+  bool firstRun;
+  uint8_t pace; // quarter notes per minute
+  uint8_t sync;
+  t_melody melodies[NUM_OF_CHANNELS];
+} t_melodies;
+
+void sequencerInit();
+uint16_t sequencerPlayMelodies(t_melodies *melodies);
+
+
+#endif // _SEQUENCER_H_

sound-driver/sn76489an.c

@@ -0,0 +1,171 @@
+#include <msp430g2553.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#include "psg.h"
+#include "scheduler.h"
+
+
+// generated using utils/calc-76489an.py
+const uint16_t frequencyCodes[8][12] = {
+  { 3420, 3229, 3047, 2876, 2715, 2562, 2419, 2283, 2155, 2034, 1920, 1812 }, 
+  { 1710, 1614, 1524, 1438, 1357, 1281, 1209, 1141, 1077, 1017, 960, 906 }, 
+  { 855, 807, 762, 719, 679, 641, 605, 571, 539, 508, 480, 453 }, 
+  { 428, 404, 381, 360, 339, 320, 302, 285, 269, 254, 240, 226 }, 
+  { 214, 202, 190, 180, 170, 160, 151, 143, 135, 127, 120, 113 }, 
+  { 107, 101, 95, 90, 85, 80, 76, 71, 67, 64, 60, 57 }, 
+  { 53, 50, 48, 45, 42, 40, 38, 36, 34, 32, 30, 28 }, 
+  { 27, 25, 24, 22, 21, 20, 19, 18, 17, 16, 15, 14 }
+};
+
+
+#define ADDR_DATA_REG P2OUT
+#define BUS_CTRL_REG P1OUT
+#define BUS_CTRL_IN_REG P1IN
+#define _CS0 BIT0
+#define _CS1 BIT1
+#define _WE BIT2
+#define READY BIT3
+
+#define CHANNEL_A_PERIOD_ADDR 0
+#define CHANNEL_A_ATTEN_ADDR 1
+#define CHANNEL_B_PERIOD_ADDR 2
+#define CHANNEL_B_ATTEN_ADDR 3
+#define CHANNEL_C_PERIOD_ADDR 4
+#define CHANNEL_C_ATTEN_ADDR 5
+
+#define IGNORE_OCTET 0xff
+
+uint8_t psgAmplitudeShadowValue[3];
+
+static void delay() {
+  asm volatile (
+      "push r12\n"
+      "mov.w #5, r12\n"
+      "loop:\n"
+      "dec.w r12\n"
+      "jnz loop\n"
+      "pop r12\n"
+  );
+}
+
+inline static void WRITE_CYCLE(uint8_t chipNo) {
+  if (chipNo == 0) {
+    BUS_CTRL_REG &= ~_CS0;
+  } else {
+    BUS_CTRL_REG &= ~_CS1;
+  }
+
+  BUS_CTRL_REG &= ~_WE;
+
+  delay();
+
+  while ((BUS_CTRL_IN_REG & READY) == 0);
+
+  BUS_CTRL_REG |= _WE;
+
+  if (chipNo == 0) {
+    BUS_CTRL_REG |= _CS0;
+  } else {
+    BUS_CTRL_REG |= _CS1;
+  }
+
+  delay();
+}
+
+static void psgWrite(uint8_t chipNo, uint8_t value) {
+  ADDR_DATA_REG = value;
+  WRITE_CYCLE(chipNo);
+}
+
+static void psgWriteFrequency(uint8_t channel, uint16_t frequencyCode) {
+  uint8_t chipNo = channel / 3;
+  uint8_t regAddr = (channel % 3) * 2;
+
+  // bit order in frequncyCode and order in octet on data bus are reversed
+  // see datacheat cp. 1 and cp. 6
+  uint8_t firstOctet = 0x01;
+  firstOctet |= ((regAddr & 0x04) > 1);
+  firstOctet |= ((regAddr & 0x02) < 1);
+  firstOctet |= ((regAddr & 0x01) < 3);
+  uint8_t lowerPart = frequencyCode & 0x0f;
+  firstOctet |= ((lowerPart & 0x08) << 1);
+  firstOctet |= ((lowerPart & 0x04) << 3);
+  firstOctet |= ((lowerPart & 0x02) << 5);
+  firstOctet |= ((lowerPart & 0x01) << 7);
+
+  uint8_t secondOctet = 0;
+  uint8_t upperPart = (frequencyCode & 0x03f0) >> 4;
+  secondOctet |= ((upperPart & 0x20) >> 3);
+  secondOctet |= ((upperPart & 0x10) >> 1);
+  secondOctet |= ((upperPart & 0x08) << 1);
+  secondOctet |= ((upperPart & 0x04) << 3);
+  secondOctet |= ((upperPart & 0x02) << 5);
+  secondOctet |= ((upperPart & 0x01) << 7);
+
+  ADDR_DATA_REG = firstOctet;
+  WRITE_CYCLE(chipNo);
+
+  ADDR_DATA_REG = secondOctet;
+  WRITE_CYCLE(chipNo);
+}
+
+void psgAmplitude(uint8_t channel, uint8_t volume) {
+  psgAmplitudeShadowValue[channel] = volume;
+  uint8_t chipNo = channel / 3;
+  uint8_t regAddr = ((channel % 3) * 2) + 1;
+
+  uint8_t attenuation = 15 - volume;
+
+  uint8_t firstOctet = 0x01;
+  firstOctet |= ((regAddr & 0x04) >> 1);
+  firstOctet |= ((regAddr & 0x02) << 1);
+  firstOctet |= ((regAddr & 0x01) << 3);
+  firstOctet |= ((attenuation & 0x01) << 7);
+  firstOctet |= ((attenuation & 0x02) << 5);
+  firstOctet |= ((attenuation & 0x04) << 3);
+  firstOctet |= ((attenuation & 0x08) << 1);
+
+  ADDR_DATA_REG = firstOctet;
+  WRITE_CYCLE(chipNo);
+}
+
+void psgPlayTone(uint8_t channel, uint8_t volume, t_octave octave, t_note note) {
+  if (note == e_Pause) {
+    psgAmplitude(channel, 0);
+  } else {
+//    if (psgAmplitudeShadowValue[channel] == 0) {
+      psgAmplitude(channel, volume);
+//    }
+    psgWriteFrequency(channel, frequencyCodes[octave][note]);
+  }
+}
+
+void psgInit() {
+  // address/data bus
+  P2DIR = 0xff;
+  P2SEL = 0;
+  P2SEL2 = 0;
+
+  // bus control lines
+  //   output:
+  //     BIT0: /CS chip 0
+  //     BIT1: /CS chip 1
+  //     BIT2: /WE
+  //   input:
+  //     BIT3: READY
+  P1DIR |= BIT0 | BIT1 | BIT2;
+  P1DIR &= ~BIT3;
+  // immediately disable all outputs, all are active low
+  P1OUT |= BIT0 | BIT1 | BIT2;
+
+  // shutdown all channels including noise
+  psgWrite(0, 0b11111001);
+  psgWrite(0, 0b11111101);
+  psgWrite(0, 0b11111011);
+  psgWrite(0, 0b11111111);
+
+//  psgPlayTone(0, 5, e_O_3, e_A);
+  psgAmplitude(0, 3);
+}
+

sound-driver/spi.c

@@ -0,0 +1,29 @@
+#include <msp430g2553.h>
+#include "spi.h"
+
+
+void __attribute__ ((interrupt (USCIAB0RX_VECTOR))) receive() {
+  if (UC0IFG & UCB0RXIFG) {
+    // receive an octet
+  }
+}
+
+
+void spiInit() {
+  // SPI slave
+  // BIT4: UCB0STE
+  // BIT5: UCB0CLK
+  // BIT6: UCB0SOMI
+  // BIT7: UCB0SIMO
+  P1SEL |= BIT4 | BIT5 | BIT6 | BIT7;
+  P1SEL2 |= BIT4 | BIT5 | BIT6 | BIT7;
+
+  // most significant bit first, enable STE
+  UCB0CTL0 = UCSYNC | UCMSB | UCMODE_2;
+  UCB0CTL1 = 0x00;
+
+  // enable RX interrupt
+  UC0IE |= UCB0RXIE;
+}
+
+

sound-driver/spi.h

@@ -0,0 +1,9 @@
+#ifndef _SPI_H_
+#define _SPI_H_
+
+
+void spiInit();
+
+
+
+#endif // _SPI_H_

sound-driver/utils/calc-76489an.py

@@ -0,0 +1,64 @@
+N = 3579545.0
+factor = 1.0594631
+base = 440.0
+
+frequencies = []
+
+BEFORE_A = 46
+f = base
+for i in range (BEFORE_A):
+    idx = BEFORE_A - i - 1
+    print(f"{idx}: {f}")
+    frequencies.append(f)
+    f = base / factor
+    base = f
+frequencies.reverse()
+
+AFTER_A = 50
+base = 440.0
+for i in range(AFTER_A):
+    idx = BEFORE_A + i
+    f = base * factor
+    print(f"{idx}: {f}")
+    frequencies.append(f)
+    base = f
+
+# print(f"{frequencies}")
+
+codes = []
+for i in range(len(frequencies)):
+    codes.append(round(N / (32.0 * frequencies[i])))
+
+
+#const uint16_t frequencyCodes[8][12] = {
+#  //    C,   Cis,     D,   Dis,     E,     F,   Fis,     G,   Gis,     A,   Ais,     H
+#  { 06535, 06234, 05747, 05474, 05233, 05002, 04563, 04353, 04153, 03762, 03600, 03424 },  // Octave 1
+#  { 03256, 03116, 02764, 02636, 02515, 02401, 02271, 02165, 02065, 01771, 01700, 01612 },  // Octave 2
+#  { 01527, 01447, 01372, 01317, 01247, 01201, 01135, 01073, 01033, 00774, 00740, 00705 },  // Octave 3
+#  { 00654, 00624, 00575, 00550, 00523, 00500, 00456, 00435, 00415, 00376, 00360, 00342 },  // Octave 4
+#  { 00326, 00312, 00276, 00264, 00252, 00240, 00227, 00217, 00207, 00177, 00170, 00161 },  // Octave 5
+#  { 00153, 00145, 00137, 00132, 00125, 00120, 00114, 00107, 00103, 00100, 00074, 00071 },  // Octave 6
+#  { 00065, 00062, 00060, 00055, 00052, 00050, 00046, 00044, 00042, 00040, 00036, 00034 },  // Octave 7
+#  { 00033, 00031, 00030, 00026, 00025, 00024, 00023, 00022, 00021, 00020, 00017, 00016 }   // Octave 8
+#};
+
+
+
+print("const uint16_t frequencyCodes[8][12] = {")
+step = 12
+for i in range(len(codes)):
+    if (i % step == 0):
+        print("  { ", end='')
+    print(f"{codes[i]}", end='')
+    if ((i+1) % step != 0):
+        print(", ", end='')
+    if ((i+1) % step == 0):
+        print(" }", end='')
+        if ((i+1) != len(codes)):
+            print(", ")
+        else:
+            print()
+print("};")
+
+
+