49 lines
1.3 KiB
C++
49 lines
1.3 KiB
C++
#undef HID_ENABLED
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// Arduino Due ADC->DMA->USB 1MSPS
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// by stimmer
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// from http://forum.arduino.cc/index.php?topic=137635.msg1136315#msg1136315
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// Input: Analog in A0
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// Output: Raw stream of uint16_t in range 0-4095 on Native USB Serial/ACM
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// on linux, to stop the OS cooking your data:
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// stty -F /dev/ttyACM0 raw -iexten -echo -echoe -echok -echoctl -echoke -onlcr
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volatile int bufn,obufn;
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uint16_t buf[4][256]; // 4 buffers of 256 readings
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void ADC_Handler(){ // move DMA pointers to next buffer
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int f=ADC->ADC_ISR;
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if (f&(1<<27)){
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bufn=(bufn+1)&3;
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ADC->ADC_RNPR=(uint32_t)buf[bufn];
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ADC->ADC_RNCR=256;
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}
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}
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void setup(){
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SerialUSB.begin(0);
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while(!SerialUSB);
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pmc_enable_periph_clk(ID_ADC);
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adc_init(ADC, SystemCoreClock, ADC_FREQ_MAX, ADC_STARTUP_FAST);
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ADC->ADC_MR |=0x80; // free running
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ADC->ADC_CHER=0x80;
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NVIC_EnableIRQ(ADC_IRQn);
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ADC->ADC_IDR=~(1<<27);
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ADC->ADC_IER=1<<27;
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ADC->ADC_RPR=(uint32_t)buf[0]; // DMA buffer
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ADC->ADC_RCR=256;
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ADC->ADC_RNPR=(uint32_t)buf[1]; // next DMA buffer
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ADC->ADC_RNCR=256;
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bufn=obufn=1;
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ADC->ADC_PTCR=1;
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ADC->ADC_CR=2;
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}
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void loop(){
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while(obufn==bufn); // wait for buffer to be full
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SerialUSB.write((uint8_t *)buf[obufn],512); // send it - 512 bytes = 256 uint16_t
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obufn=(obufn+1)&3;
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}
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