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import { describe, expect, it, vi } from 'vitest';
import { CPU } from '../cpu/cpu';
import { asmProgram, TestProgramRunner } from '../utils/test-utils';
import { adcConfig, ADCMuxInputType, AVRADC } from './adc';
const R16 = 16;
const R17 = 17;
const ADMUX = 0x7c;
const REFS0 = 1 << 6;
const ADCSRA = 0x7a;
const ADEN = 1 << 7;
const ADSC = 1 << 6;
const ADPS0 = 1 << 0;
const ADPS1 = 1 << 1;
const ADPS2 = 1 << 2;
const ADCH = 0x79;
const ADCL = 0x78;
describe('ADC', () => {
it('should successfuly perform an ADC conversion', () => {
const { program } = asmProgram(`
; register addresses
_REPLACE ADMUX, ${ADMUX}
_REPLACE ADCSRA, ${ADCSRA}
_REPLACE ADCH, ${ADCH}
_REPLACE ADCL, ${ADCL}
; Configure mux - channel 0, reference: AVCC with external capacitor at AREF pin
ldi r24, ${REFS0}
sts ADMUX, r24
; Start conversion with 128 prescaler
ldi r24, ${ADEN | ADSC | ADPS0 | ADPS1 | ADPS2}
sts ADCSRA, r24
; Wait until conversion is complete
waitComplete:
lds r24, ${ADCSRA}
andi r24, ${ADSC}
brne waitComplete
; Read the result
lds r16, ${ADCL}
lds r17, ${ADCH}
break
`);
const cpu = new CPU(program);
const adc = new AVRADC(cpu, adcConfig);
const runner = new TestProgramRunner(cpu);
const adcReadSpy = vi.spyOn(adc, 'onADCRead');
adc.channelValues[0] = 2.56; // should result in 2.56/5*1024 = 524
// Setup
runner.runInstructions(4);
expect(adcReadSpy).toHaveBeenCalledWith({ channel: 0, type: ADCMuxInputType.SingleEnded });
// Run the "waitComplete" loop for a few cycles
runner.runInstructions(12);
cpu.cycles += 128 * 25; // skip to the end of the conversion
cpu.tick();
// Now read the result
runner.runInstructions(5);
const low = cpu.data[R16];
const high = cpu.data[R17];
expect((high << 8) | low).toEqual(524); // 2.56 volts - see above
});
it('should read 0 when the ADC peripheral is not enabled', () => {
// This behavior was verified on real hardware, using the following test program:
// https://wokwi.com/arduino/projects/309156042450666050
// Thanks Oscar Oomens for spotting this!
const { program } = asmProgram(`
; register addresses
_REPLACE ADMUX, ${ADMUX}
_REPLACE ADCSRA, ${ADCSRA}
_REPLACE ADCH, ${ADCH}
_REPLACE ADCL, ${ADCL}
; Load some initial value into r16/r17 to make sure we actually read 0 later
ldi r16, 0xff
ldi r17, 0xff
; Configure mux - channel 0, reference: AVCC with external capacitor at AREF pin
ldi r24, ${REFS0}
sts ADMUX, r24
; Start conversion with 128 prescaler, but without enabling the ADC
ldi r24, ${ADSC | ADPS0 | ADPS1 | ADPS2}
sts ADCSRA, r24
; Wait until conversion is complete
waitComplete:
lds r24, ${ADCSRA}
andi r24, ${ADSC}
brne waitComplete
; Read the result
lds r16, ${ADCL}
lds r17, ${ADCH}
break
`);
const cpu = new CPU(program);
const adc = new AVRADC(cpu, adcConfig);
const runner = new TestProgramRunner(cpu, () => {
/* do nothing on break */
});
const adcReadSpy = vi.spyOn(adc, 'onADCRead');
adc.channelValues[0] = 2.56; // should result in 2.56/5*1024 = 524
// Setup
runner.runInstructions(6);
expect(adcReadSpy).not.toHaveBeenCalled();
// Run the "waitComplete" loop for a few cycles
runner.runInstructions(12);
cpu.cycles += 128 * 25; // skip to the end of the conversion
cpu.tick();
// Now read the result
runner.runToBreak();
const low = cpu.data[R16];
const high = cpu.data[R17];
expect((high << 8) | low).toEqual(0); // We should read 0 since the ADC hasn't been enabled
});
});
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