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testYMZ284.ino
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testYMZ284.ino
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/* testYMZ284 --- simple sketch to drive the YMZ284 sound chip 2017-01-28 */
/* Copyright (c) 2017 John Honniball */
#define CS_PIN (2)
#define CLK_PIN (3)
#define WR_PIN (4)
#define A0_PIN (5)
#define D0_PIN (6)
#define TONEPERIODA_REG (0)
#define TONEPERIODB_REG (2)
#define TONEPERIODC_REG (4)
#define NOISEPERIOD_REG (6)
#define ENABLE_REG (7)
#define AMPLITUDEA_REG (8)
#define AMPLITUDEB_REG (9)
#define AMPLITUDEC_REG (10)
#define ENVELOPEPERIOD_REG (11)
#define ENVELOPEMODE_REG (13)
#define IOPORTA_REG (14) // AY-3-8910 only; not present on YMZ284
#define IOPORTB_REG (15)
#define CHANNELA (0)
#define CHANNELB (1)
#define CHANNELC (2)
#define IOPORTA (0)
#define IOPORTB (1)
#define AMPLITUDE_ENV (16)
#define AMPLITUDE_MAX (15)
#define AMPLITUDE_OFF (0)
#define ENV_CONT (8)
#define ENV_ATTACK (4)
#define ENV_ALT (2)
#define ENV_HOLD (1)
uint8_t EnableReg = 0;
void setup(void)
{
int i;
Serial.begin(9600);
initPSG();
setTonePeriod(CHANNELA, 142); // (2000000 / 32) / frequency
setNoisePeriod(15);
setToneEnable(CHANNELA, true);
setAmplitude(CHANNELA, AMPLITUDE_ENV);
setAmplitude(CHANNELB, AMPLITUDE_OFF);
setAmplitude(CHANNELC, AMPLITUDE_OFF);
setEnvelopePeriod(1024);
setEnvelopeMode(ENV_CONT | ENV_ALT);
}
void loop(void)
{
int ana;
ana = analogRead(0);
setEnvelopePeriod(ana);
ana = analogRead(1);
setTonePeriod(CHANNELA, ana);
delay(20);
}
/* initPSG --- initialise chip and disable all noise and tone channels */
void initPSG(void)
{
int i;
// Generate 2MHz clock on Pin 3
pinMode(CLK_PIN, OUTPUT);
TCCR2A = 0x23;
TCCR2B = 0x09;
OCR2A = 7;
OCR2B = 1;
delay(10);
// Chip Select pin
pinMode(CS_PIN, OUTPUT);
digitalWrite(CS_PIN, HIGH);
// Write pin
pinMode(WR_PIN, OUTPUT);
digitalWrite(WR_PIN, HIGH);
// A0 pin
pinMode(A0_PIN, OUTPUT);
digitalWrite(A0_PIN, LOW);
// D0-D7 pins
for (i = D0_PIN; i < (D0_PIN + 8); i++) {
pinMode(i, OUTPUT);
digitalWrite(i, LOW);
}
EnableReg = 0x3f; // All noise and tone channels disabled
aywrite(ENABLE_REG, EnableReg);
aywrite(IOPORTB_REG, 0);
}
/* setToneEnable --- enable or disable tone generation on a given channel */
void setToneEnable(const int channel, const int enable)
{
const uint8_t mask = 1 << channel;
if (enable) {
EnableReg &= ~mask;
}
else {
EnableReg |= mask;
}
aywrite(ENABLE_REG, EnableReg);
}
/* setNoiseEnable --- enable or disable noise generation on a given channel */
void setNoiseEnable(const int channel, const int enable)
{
const uint8_t mask = 1 << (3 + channel);
if (enable) {
EnableReg &= ~mask;
}
else {
EnableReg |= mask;
}
aywrite(ENABLE_REG, EnableReg);
}
/* setPortDirection --- set I/O port to input or output */
void setPortDirection(const int channel, const int direction)
{
const uint8_t mask = 1 << (6 + channel);
if (direction == INPUT) {
EnableReg &= ~mask;
}
else if (direction == OUTPUT) {
EnableReg |= mask;
}
aywrite(ENABLE_REG, EnableReg);
}
/* setPortOutputs --- send a byte to the output port pins */
void setPortOutputs(const int channel, const int val)
{
aywrite(IOPORTA_REG + channel, val);
}
/* setAmplitude --- set amplitude for a given channel */
void setAmplitude(const int channel, const int amplitude)
{
aywrite(AMPLITUDEA_REG + channel, amplitude);
}
/* setTonePeriod --- set tone period for a given channel */
void setTonePeriod(const int channel, const unsigned int period)
{
aywrite(TONEPERIODA_REG + (channel * 2), period & 0xff);
aywrite(TONEPERIODA_REG + (channel * 2) + 1, period >> 8);
}
/* setNoisePeriod --- set period of the noise generator */
void setNoisePeriod(const int period)
{
aywrite(NOISEPERIOD_REG, period);
}
/* setEnvelopePeriod --- set period of envelope generator */
void setEnvelopePeriod(const unsigned int envelope)
{
aywrite(ENVELOPEPERIOD_REG, envelope & 0xff);
aywrite(ENVELOPEPERIOD_REG + 1, envelope >> 8);
}
/* setEnvelopeMode --- set mode of envelope generator */
void setEnvelopeMode(const unsigned int mode)
{
aywrite(ENVELOPEMODE_REG, mode);
}
/* aywrite --- write a byte to a given register in the PSG */
void aywrite(const int reg, const int val)
{
ymzwrite(LOW, reg);
ymzwrite(HIGH, val);
}
/* ymzwrite --- emulate a bus cycle to write a single byte to the chip */
void ymzwrite(const int a0, const int val)
{
int i;
#ifdef SLOW
digitalWrite(A0_PIN, a0);
for (i = 0; i < 8; i++) {
if (val & (1 << i))
digitalWrite(D0_PIN + i, HIGH);
else
digitalWrite(D0_PIN + i, LOW);
}
// CS LOW
digitalWrite(CS_PIN, LOW);
// WR LOW
digitalWrite(WR_PIN, LOW);
// WR HIGH
digitalWrite(WR_PIN, HIGH);
// CS HIGH
digitalWrite(CS_PIN, HIGH);
#else
// A0 on Arduino Pin 5, Port D bit 5
if (a0)
PORTD |= (1 << 5);
else
PORTD &= ~(1 << 5);
// D0-D1 on Port D bits 6 and 7; D2-D7 on Port B bits 0-5
PORTD = (PORTD & 0x3f) | ((val & 0x03) << 6);
PORTB = val >> 2;
// CS on Arduino Pin 2, Port D bit 2
PORTD &= ~(1 << 2);
// WR on Arduino Pin 4, Port D bit 4
PORTD &= ~(1 << 4);
// Minimum CS LOW time is 30ns; no need for NOP here
// WR on Arduino Pin 4, Port D bit 4
PORTD |= (1 << 4);
// CS on Arduino Pin 2, Port D bit 2
PORTD |= (1 << 2);
#endif
}