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@ -8,14 +8,20 @@
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// how many samples we want to skip between two samples we keep (can be used to lower the sampling frequency)
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#define SkipSamples 0 |
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byte regularEncodedFrequency; |
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byte burstEncodedFrequency; |
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const int BufferSize = 512; |
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int regularADCSRA; |
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int burstADCSRA; |
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const int BufferSize = 128; |
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const int BurstBufferSize = 1024; |
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byte buffer1[BufferSize]; |
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byte buffer2[BufferSize]; |
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byte* backBuffer = buffer1; |
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byte burstBuffer[BurstBufferSize]; |
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volatile byte* backBuffer = buffer1; |
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volatile short backBufferPos = 0; |
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byte samplesSkipped = SkipSamples; |
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unsigned long backBufferStartTime = micros(); |
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volatile unsigned long backBufferStartTime = micros(); |
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SerialChannel oscilloscope("oscilloscope"); |
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SerialChannel debug("debug"); |
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@ -39,19 +45,34 @@ void setup()
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ADMUX |= (1 << REFS0); //set reference voltage
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ADMUX |= (1 << ADLAR); //left align the ADC value- so we can read highest 8 bits from ADCH register only
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int ADPS = (1 << ADPS2) | (0 << ADPS1) | (1 << ADPS0); |
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ADCSRA |= ADPS; //set ADC clock with 32 prescaler- 16mHz/32=500KHz ; 13 cycles for a conversion which means 38000 samples per second
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ADCSRA |= (1 << ADATE); //enabble auto trigger
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ADCSRA |= (1 << ADIE); //enable interrupts when measurement complete
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ADCSRA |= (1 << ADEN); //enable ADC
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ADCSRA |= (1 << ADSC); //start ADC measurements
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byte skipSamples = 0; |
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#if SkipSamples > 0 |
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skipSamples = SkipSamples; |
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#endif |
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int ADPS = (1 << ADPS2) | (0 << ADPS1) | (1 << ADPS0); |
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regularADCSRA = 0; |
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regularADCSRA |= ADPS; //set ADC clock with 32 prescaler- 16mHz/32=500KHz ; 13 cycles for a conversion which means 38000 samples per second
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regularADCSRA |= (1 << ADATE); //enabble auto trigger
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regularADCSRA |= (1 << ADIE); //enable interrupts when measurement complete
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regularADCSRA |= (1 << ADEN); //enable ADC
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regularADCSRA |= (1 << ADSC); //start ADC measurements
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regularEncodedFrequency = (byte)ADPS; |
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regularEncodedFrequency |= skipSamples << 3; |
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ADCSRA = regularADCSRA; |
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ADPS = (0 << ADPS2) | (1 << ADPS1) | (1 << ADPS0); |
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burstADCSRA = 0; |
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burstADCSRA |= ADPS; //set ADC clock with 32 prescaler- 16mHz/32=500KHz ; 13 cycles for a conversion which means 38000 samples per second
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burstADCSRA |= (1 << ADATE); //enabble auto trigger
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burstADCSRA |= (1 << ADIE); //enable interrupts when measurement complete
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burstADCSRA |= (1 << ADEN); //enable ADC
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burstADCSRA |= (1 << ADSC); //start ADC measurements
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regularEncodedFrequency = (byte)ADPS; |
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byte skipSamples = 0; |
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#if SkipSamples > 0 |
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skipSamples = SkipSamples; |
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#endif |
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regularEncodedFrequency |= skipSamples << 3; |
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burstEncodedFrequency = (byte)ADPS; |
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burstEncodedFrequency |= skipSamples << 3; |
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sei();//enable interrupts
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@ -60,20 +81,26 @@ void setup()
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void loop() |
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{ |
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while(backBufferPos < BufferSize / 2) ; |
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while(backBufferPos < BufferSize / 2 || (backBuffer == burstBuffer && backBufferPos < BurstBufferSize - 1)) ; |
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cli();//disable interrupts
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byte* currentBuffer = backBuffer; |
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byte* currentBuffer = (byte*)backBuffer; |
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short currentBufferSize = backBufferPos; |
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backBuffer = (backBuffer == buffer1 ? buffer2 : buffer1); |
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backBufferPos = 0; |
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if(currentBuffer == burstBuffer) |
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{ |
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ADCSRA = regularADCSRA; |
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} |
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sei();//enable interrupts
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unsigned long currentBufferStartTime = backBufferStartTime; |
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backBufferStartTime = micros(); |
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digitalWrite(LEDPin, LOW); |
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byte encodedFrequency = currentBuffer == burstBuffer ? burstEncodedFrequency : regularEncodedFrequency; |
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//Serial.write(currentBuffer, currentBufferSize);
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oscilloscope.beginWrite(currentBufferSize + 1, currentBufferStartTime); |
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oscilloscope.continueWrite(®ularEncodedFrequency, 1); |
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oscilloscope.continueWrite(&encodedFrequency, 1); |
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oscilloscope.continueWrite(currentBuffer, currentBufferSize); |
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} |
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@ -87,12 +114,31 @@ ISR(ADC_vect) {//when new ADC value ready
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#endif |
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backBuffer[backBufferPos++] = sample; |
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if(backBufferPos >= BufferSize) |
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if(backBuffer == burstBuffer) |
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{ |
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// overflow of back buffer, we loose the current sample
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digitalWrite(LEDPin, HIGH); |
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backBufferPos = BufferSize - 1; |
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if(backBufferPos >= BurstBufferSize) |
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{ |
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backBufferPos = BurstBufferSize - 1; |
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} |
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} |
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else |
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{ |
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if(backBufferPos >= BufferSize) |
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{ |
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// overflow of back buffer, we loose the current sample
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digitalWrite(LEDPin, HIGH); |
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backBufferPos = BufferSize - 1; |
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} |
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} |
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// switch to burst mode if the trigger condition is met
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/*if(backBuffer != burstBuffer && sample < 127)
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{ |
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backBuffer = burstBuffer; |
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ADCSRA = burstADCSRA; |
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backBufferPos = 0; |
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backBufferStartTime = micros(); |
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}*/ |
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} |
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void onewireInterrupt(void) |
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