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@NT7S NT7S/DACZero.ino
Created Jan 18, 2017

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DAC Sine Wave on Empyrean/Arduino Zero
uint8_t sine_wave[256] = {
0x80, 0x83, 0x86, 0x89, 0x8C, 0x90, 0x93, 0x96,
0x99, 0x9C, 0x9F, 0xA2, 0xA5, 0xA8, 0xAB, 0xAE,
0xB1, 0xB3, 0xB6, 0xB9, 0xBC, 0xBF, 0xC1, 0xC4,
0xC7, 0xC9, 0xCC, 0xCE, 0xD1, 0xD3, 0xD5, 0xD8,
0xDA, 0xDC, 0xDE, 0xE0, 0xE2, 0xE4, 0xE6, 0xE8,
0xEA, 0xEB, 0xED, 0xEF, 0xF0, 0xF1, 0xF3, 0xF4,
0xF5, 0xF6, 0xF8, 0xF9, 0xFA, 0xFA, 0xFB, 0xFC,
0xFD, 0xFD, 0xFE, 0xFE, 0xFE, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFE, 0xFE, 0xFE, 0xFD,
0xFD, 0xFC, 0xFB, 0xFA, 0xFA, 0xF9, 0xF8, 0xF6,
0xF5, 0xF4, 0xF3, 0xF1, 0xF0, 0xEF, 0xED, 0xEB,
0xEA, 0xE8, 0xE6, 0xE4, 0xE2, 0xE0, 0xDE, 0xDC,
0xDA, 0xD8, 0xD5, 0xD3, 0xD1, 0xCE, 0xCC, 0xC9,
0xC7, 0xC4, 0xC1, 0xBF, 0xBC, 0xB9, 0xB6, 0xB3,
0xB1, 0xAE, 0xAB, 0xA8, 0xA5, 0xA2, 0x9F, 0x9C,
0x99, 0x96, 0x93, 0x90, 0x8C, 0x89, 0x86, 0x83,
0x80, 0x7D, 0x7A, 0x77, 0x74, 0x70, 0x6D, 0x6A,
0x67, 0x64, 0x61, 0x5E, 0x5B, 0x58, 0x55, 0x52,
0x4F, 0x4D, 0x4A, 0x47, 0x44, 0x41, 0x3F, 0x3C,
0x39, 0x37, 0x34, 0x32, 0x2F, 0x2D, 0x2B, 0x28,
0x26, 0x24, 0x22, 0x20, 0x1E, 0x1C, 0x1A, 0x18,
0x16, 0x15, 0x13, 0x11, 0x10, 0x0F, 0x0D, 0x0C,
0x0B, 0x0A, 0x08, 0x07, 0x06, 0x06, 0x05, 0x04,
0x03, 0x03, 0x02, 0x02, 0x02, 0x01, 0x01, 0x01,
0x01, 0x01, 0x01, 0x01, 0x02, 0x02, 0x02, 0x03,
0x03, 0x04, 0x05, 0x06, 0x06, 0x07, 0x08, 0x0A,
0x0B, 0x0C, 0x0D, 0x0F, 0x10, 0x11, 0x13, 0x15,
0x16, 0x18, 0x1A, 0x1C, 0x1E, 0x20, 0x22, 0x24,
0x26, 0x28, 0x2B, 0x2D, 0x2F, 0x32, 0x34, 0x37,
0x39, 0x3C, 0x3F, 0x41, 0x44, 0x47, 0x4A, 0x4D,
0x4F, 0x52, 0x55, 0x58, 0x5B, 0x5E, 0x61, 0x64,
0x67, 0x6A, 0x6D, 0x70, 0x74, 0x77, 0x7A, 0x7D
};
volatile uint8_t t = 0;
void setup() {
// Set up the generic clock (GCLK4) used to clock timers
REG_GCLK_GENDIV = GCLK_GENDIV_DIV(3) | // Divide the 48MHz clock source by divisor 3: 48MHz/3=16MHz
GCLK_GENDIV_ID(4); // Select Generic Clock (GCLK) 4
while (GCLK->STATUS.bit.SYNCBUSY); // Wait for synchronization
REG_GCLK_GENCTRL = GCLK_GENCTRL_IDC | // Set the duty cycle to 50/50 HIGH/LOW
GCLK_GENCTRL_GENEN | // Enable GCLK4
GCLK_GENCTRL_SRC_DFLL48M | // Set the 48MHz clock source
GCLK_GENCTRL_ID(4); // Select GCLK4
while (GCLK->STATUS.bit.SYNCBUSY); // Wait for synchronization
// Feed GCLK4 to TC4 and TC5
REG_GCLK_CLKCTRL = GCLK_CLKCTRL_CLKEN | // Enable GCLK4 to TC4 and TC5
GCLK_CLKCTRL_GEN_GCLK4 | // Select GCLK4
GCLK_CLKCTRL_ID_TC4_TC5; // Feed the GCLK4 to TC4 and TC5
while (GCLK->STATUS.bit.SYNCBUSY); // Wait for synchronization
REG_TC4_CTRLA |= TC_CTRLA_MODE_COUNT8; // Set the counter to 8-bit mode
while (TC4->COUNT8.STATUS.bit.SYNCBUSY); // Wait for synchronization
REG_TC4_COUNT8_CC0 = 0x0A; // Set the TC4 CC0 register to some arbitary value
//TC4->COUNT8.CC[0].reg = 0x04;
while (TC4->COUNT8.STATUS.bit.SYNCBUSY); // Wait for synchronization
REG_TC4_COUNT8_CC1 = 0xAA; // Set the TC4 CC1 register to some arbitary value
while (TC4->COUNT8.STATUS.bit.SYNCBUSY); // Wait for synchronization
REG_TC4_COUNT8_PER = 0xFF; // Set the PER (period) register to its maximum value
while (TC4->COUNT8.STATUS.bit.SYNCBUSY); // Wait for synchronization
//NVIC_DisableIRQ(TC4_IRQn);
//NVIC_ClearPendingIRQ(TC4_IRQn);
NVIC_SetPriority(TC4_IRQn, 0); // Set the Nested Vector Interrupt Controller (NVIC) priority for TC4 to 0 (highest)
NVIC_EnableIRQ(TC4_IRQn); // Connect TC4 to Nested Vector Interrupt Controller (NVIC)
REG_TC4_INTFLAG |= TC_INTFLAG_MC1 | TC_INTFLAG_MC0 | TC_INTFLAG_OVF; // Clear the interrupt flags
REG_TC4_INTENSET = TC_INTENSET_MC1 | TC_INTENSET_MC0 | TC_INTENSET_OVF; // Enable TC4 interrupts
// REG_TC4_INTENCLR = TC_INTENCLR_MC1 | TC_INTENCLR_MC0 | TC_INTENCLR_OVF; // Disable TC4 interrupts
//REG_TC4_CTRLA |= TC_CTRLA_WAVEGEN_MFRQ;
//while (TC4->COUNT8.STATUS.bit.SYNCBUSY);
REG_TC4_CTRLA |= TC_CTRLA_PRESCALER_DIV1 | // Set prescaler to 64, 16MHz/64 = 256kHz
TC_CTRLA_ENABLE; // Enable TC4
while (TC4->COUNT8.STATUS.bit.SYNCBUSY); // Wait for synchronization
analogWriteResolution(8);
}
void loop() {
// put your main code here, to run repeatedly:
//analogWrite(A0, sine_wave[REG_TC4_COUNT8_COUNT]);
analogWrite(A0, sine_wave[t]);
}
void TC4_Handler() // Interrupt Service Routine (ISR) for timer TC4
{
// Check for overflow (OVF) interrupt
if (TC4->COUNT8.INTFLAG.bit.OVF && TC4->COUNT8.INTENSET.bit.OVF)
{
//t++;
REG_TC4_INTFLAG = TC_INTFLAG_OVF; // Clear the OVF interrupt flag
}
// Check for match counter 0 (MC0) interrupt
if (TC4->COUNT8.INTFLAG.bit.MC0 && TC4->COUNT8.INTENSET.bit.MC0)
{
// Put your counter compare 0 (CC0) code here:
// ...
t++;
//REG_TC4_INTFLAG = TC_INTFLAG_MC0; // Clear the MC0 interrupt flag
TC4->COUNT8.INTFLAG.bit.MC0 = 1;
}
// Check for match counter 1 (MC1) interrupt
if (TC4->COUNT8.INTFLAG.bit.MC1 && TC4->COUNT8.INTENSET.bit.MC1)
{
// Put your counter compare 1 (CC1) code here:
// ...
//t++;
REG_TC4_INTFLAG = TC_INTFLAG_MC1; // Clear the MC1 interrupt flag
}
}
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