95 lines
2.5 KiB
C++
95 lines
2.5 KiB
C++
/**
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* SN76489 sound chip test
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*
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* DATA BUS IS: 2, 3, 4, 5, 6, 7, 8, 9 (NOTE: 2 is D0, but D0 is the MSB)
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* WE 10 (Active low)
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*/
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const byte DATA_BUS[] = {9, 8, 7, 6, 5, 4, 3, 2};
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const byte WE = 10;
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void setup() {
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// Setup pins
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for(int pin=0; pin < 8; pin++) {
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pinMode(DATA_BUS[pin], OUTPUT);
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}
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pinMode(WE, OUTPUT);
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digitalWrite(WE, HIGH);
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/* Init device (silence all channels)
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* Bits meaning:
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* 1 R0 R1 R2 A0 A1 A2 A3
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* Bit0 is 1
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* Bit1,2,3 select the channel: 001, 011, 101, 111(noise)
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* Bit4,5,6,7 selecy the attenuation (0000=full volume, 1111=silent)
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*/
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SendByte(B10011111); // Sil ch 1
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SendByte(B10111111); // Sil ch 2
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SendByte(B11011111); // Sil ch 3
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SendByte(B11111111); // Sil noise
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delay(1000);
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// Channel 1 to max volume
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SendByte(B10010000);
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/* Play note on channel 1
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* Requires sending 2 bytes.
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* Bits meaning:
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* 1 R0 R1 R2 F6 F7 F8 F9 0 0 F0 F1 F2 F3 F4 F5
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* First bit: 1=low byte (first sent), 0=high byte (last sent)
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* R0,1,2: select the channel: 000, 010, 100, 110(noise)
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* F0..9: frequency value calculated as:
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* f = REF_CLK / 32 * n
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* Where f is the resulting frequency in HZ, REF_CLK is the reference clock on pin 14 in HZ and n is F0..9
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*/
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SendByte(B10000000); SendByte(B00100000);
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delay(500);
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SendByte(B10000000); SendByte(B00010000);
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delay(500);
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SendByte(B10000000); SendByte(B00001000);
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delay(500);
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SendByte(B10011111); // Sil ch 1
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delay(1000);
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// Play notes on channel 1,2,3
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SendByte(B10010000); // Channel 1 vol max (0000)
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SendByte(B10000000); SendByte(B00100000); // Note on ch1
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delay(500);
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SendByte(B10110010); // Channel 2 vol 0010
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SendByte(B10100000); SendByte(B00010000); // Note on ch2
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delay(500);
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SendByte(B11010100); // Channel 3 vol 0100
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SendByte(B11000000); SendByte(B00001000); // Note on ch3
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delay(500);
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SendByte(B10011111); // Sil ch 1
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SendByte(B10111111); // Sil ch 2
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SendByte(B11011111); // Sil ch 3
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delay(1000);
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/*
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* Play noise on channel 4
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*/
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}
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void loop() {}
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void SendByte(byte b) {
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digitalWrite(DATA_BUS[0], (b&1)?HIGH:LOW);
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digitalWrite(DATA_BUS[1], (b&2)?HIGH:LOW);
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digitalWrite(DATA_BUS[2], (b&4)?HIGH:LOW);
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digitalWrite(DATA_BUS[3], (b&8)?HIGH:LOW);
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digitalWrite(DATA_BUS[4], (b&16)?HIGH:LOW);
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digitalWrite(DATA_BUS[5], (b&32)?HIGH:LOW);
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digitalWrite(DATA_BUS[6], (b&64)?HIGH:LOW);
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digitalWrite(DATA_BUS[7], (b&128)?HIGH:LOW);
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delay(1);
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digitalWrite(WE, LOW);
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delay(1);
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digitalWrite(WE, HIGH);
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}
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