29 lines
1.4 KiB
C
29 lines
1.4 KiB
C
#include "header.h"
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// 1.1.7 : AVCC is the supply voltage pin for the A/D Converter, PC3:0, and ADC7:6
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// 1.1.8 : AREF is the analog reference pin for the A/D Converter
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// 24.4 : frequency needs to be between 50kHz and 200kHz, for less than 10bits accuracy it can be >200kHz
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// -> Frequence_ADC = Frequance_CPU / Prescaler (Fadc = Fcpu/P):
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// - P = 2 -> Fadc = 16,000,000 / 2 = 8,000,000 = 8MHz
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// - P = 4 -> Fadc = 16,000,000 / 4 = 4,000,000 = 4MHz
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// - P = 8 -> Fadc = 16,000,000 / 8 = 2,000,000 = 2MHz
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// - P = 16 -> Fadc = 16,000,000 / 16 = 1,000,000 = 1MHz
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// - P = 32 -> Fadc = 16,000,000 / 32 = 500,000 = 500KHz
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// - P = 64 -> Fadc = 16,000,000 / 64 = 250,000 = 250KHz -> OK
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// - P = 128 -> Fadc = 16,000,000 / 128 = 125,000 = 125KHz -> OK
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#define ADC_PRESCALER 64 // Table 24-5 : can only be 2, 4, 8, 16, 32, 64, or 128
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volatile uint8_t adc_channel = 0; // Table 14-6 : alternate function for RV1 on PC0 -> ADC0, LDR on PC1 -> ADC1, NTC on PC2 -> ADC2 ...
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// read 3 analog values at 8 bits and print them in uart as hexadecimal 2-number : potentiometer RV1 (Variable Resistor), photoresistor LDR (Light Dependent Resistor), thermistor NTC (Negative Temperature Coefficient)
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int main() {
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char buffer[4];
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SREG |= ENABLE_GLOBAL_INTERRUPT; // 7.3.1 : Status Register, bit 7 : I – Global Interrupt Enable
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uart_init();
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adc_init(ADC_PRESCALER);
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timer_1B_init();
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while(1);
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} |