58 lines
1.3 KiB
C++
58 lines
1.3 KiB
C++
// Basic demo for configuring the MCP4728 4-Channel 12-bit I2C DAC
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#include <Adafruit_MCP4728.h>
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#include <Wire.h>
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Adafruit_MCP4728 mcp;
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int tuning[15];
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int edo = 7;
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int sequence[] = { 0, 0, 3, 0, 5, 0, 7, 2, 0, 0, 3, 0, 5, 0, 7, 6 };
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float voltrange = 5.0; // measured this, probably not accurate
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float octave = 4096.0 / voltrange; // number of DAC steps in an octave
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void setup(void) {
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Serial.begin(115200);
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while (!Serial)
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delay(10); // will pause Zero, Leonardo, etc until serial console opens
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if (!mcp.begin(0x64)) {
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Serial.println("Failed to find MCP4728 chip");
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while (1) {
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delay(10);
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}
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Serial.println("MCP4728 initialised");
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}
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mcp.setChannelValue(MCP4728_CHANNEL_B, 0);
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float n0 = 0;
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for( int i = 0; i < 15; i++ ) {
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tuning[i] = round(n0 + octave * (float)i / (float)edo);
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Serial.println(tuning[i]);
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}
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}
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void loop() {
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for( int i = 0; i < 16; i++ ) {
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note(sequence[i], 250);
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}
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}
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void note(int note, int dur) {
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int pot = analogRead(A0);
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float gate = (float)pot / 1024.0;
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mcp.setChannelValue(MCP4728_CHANNEL_A, tuning[note]);
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mcp.setChannelValue(MCP4728_CHANNEL_B, 4095);
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delay(round(gate * (float)dur));
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mcp.setChannelValue(MCP4728_CHANNEL_B, 0);
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delay(round((1 - gate) * (float)dur));
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}
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