From f2662355cbf4bbf12904561a9258bab3e1b031bc Mon Sep 17 00:00:00 2001 From: "Jan \"Yenya\" Kasprzak" Date: Tue, 28 Aug 2012 21:57:41 +0200 Subject: [PATCH] ADC: ignore the first reading after MUX switch --- adc.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/adc.c b/adc.c index b758721..9a5e314 100644 --- a/adc.c +++ b/adc.c @@ -18,8 +18,9 @@ static unsigned char adc_mux[] = { // pwmleds should be first #define AMBIENT_ADC N_PWMLEDS -#define LAST_ADC (sizeof(adc_mux)/sizeof(char)) -volatile static unsigned char current_adc = LAST_ADC; +#define LAST_ADC (sizeof(adc_mux)/sizeof(adc_mux[0])) +volatile static unsigned char current_adc; +static unsigned char adc_ignore; static void start_next_adc() { @@ -40,11 +41,15 @@ static void start_next_adc() found: // ADCSRB |= _BV(GSEL); // gain 8 or 32 ADMUX = adc_mux[current_adc]; // set up mux, start one-shot conversion + adc_ignore = 1; // ignore first reading after mux change ADCSRA |= _BV(ADSC); } void init_adc() { + current_adc = LAST_ADC; + adc_ignore = 1; + ADCSRA = _BV(ADEN) // enable | _BV(ADPS1) | _BV(ADPS0) // CLK/8 = 125 kHz // | _BV(ADPS2) // CLK/16 = 62.5 kHz @@ -68,6 +73,18 @@ void init_adc() ISR(ADC_vect) { // IRQ handler uint16_t adcval = ADCW; +#if 0 + log_byte(0xF3); + log_byte(current_adc); + log_word(adcval); +#endif + + if (adc_ignore) { + ADCSRA |= _BV(ADSC); + adc_ignore = 0; + return; + } + if (current_adc < N_PWMLEDS) pwmled_adc(current_adc, adcval); if (current_adc == AMBIENT_ADC) -- 2.39.3