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Events/2020/AVR: Difference between revisions
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Chet Manly (talk | contribs) |
Chet Manly (talk | contribs) |
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} | } | ||
} | } | ||
} | |||
// --- Subsidiary functions | |||
String getHeader() { | |||
// TODO - re-implement using C-style strings | |||
String header = "microseconds"; | |||
String colName; | |||
for (byte i = 0; i <= maxIndex; i++) { | |||
switch (channelSequence[i]) { | |||
case A_0 | ADCref: colName = ",CH_0"; break; | |||
case A_1 | ADCref: colName = ",CH_1"; break; | |||
case A_2 | ADCref: colName = ",CH_2"; break; | |||
case A_3 | ADCref: colName = ",CH_3"; break; | |||
case A_4 | ADCref: colName = ",CH_4"; break; | |||
case A_5 | ADCref: colName = ",CH_5"; break; | |||
default: colName = ",unknown"; break; | |||
} | |||
header += colName; | |||
} | |||
return header; | |||
} | |||
void doLowLevelConfig() { | |||
noInterrupts(); | |||
// Combine the ADC reference bits with the channel selection bits. Each value | |||
// in channelSequence should be the complete value of ADMUX for recording the | |||
// desired channel. Tables 23-3 and 23-4. | |||
// TODO - make this separate from the user-specified channel selection array? | |||
for (byte i = 0; i <= maxIndex; i++){ | |||
channelSequence[i] = channelSequence[i] | ADCref; | |||
} | |||
// Configure the Timer 0 Compare Match A interrupt. | |||
OCR0A = 64; // Keep away from the overflow (0) so micros() can update. | |||
bitSet(TIMSK0, OCIE0A); // Enable the interrupt. | |||
// Configure Timer 1 Compare Match A interrupt to trigger @ freq Hz | |||
TCCR1A = TCCR1B = TCNT1 = 0; // Clear Timer 1 settings. | |||
TCCR1B = bit(WGM12) | bit(CS12); // Count @ 62500 Hz: CTC mode, prescaler = 256. Tables 15-5 and 15-5. | |||
OCR1A = CTCmatch; // Count up to CTCmatch. Section 15.11.6. | |||
bitSet(TIMSK1, OCIE1A); // Enable Output Compare Match A interrupt. Section 15.11.8. | |||
// Enable the ADC-conversion-complete interrupt, configure ADC for | |||
// single-conversion mode, and disable the ADC. Section 23.9.2. | |||
ADCSRA |= bit(ADIE) | bit(ADIF); // sets these bits | |||
ADCSRA &= ~(bit(ADATE) | bit(ADEN)); // clears these bits | |||
ADMUX = channelSequence[0]; | |||
interrupts(); | |||
} | } | ||
</pre> | </pre> | ||