41 lines
1.7 KiB
C
41 lines
1.7 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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void int_to_hex_string(uint64_t value, char *out, uint8_t num_digits) { // num_digits : number of digit of the output, ex 2 for 3FF (1023) -> FF
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for (uint8_t i = 0; i < num_digits; ++i) {
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uint8_t shift = (num_digits - 1 - i) * 4;
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out[i] = INT_TO_HEX_CHAR((value >> shift) & 0x0F);
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}
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out[num_digits] = '\0';
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}
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// description
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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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while(1) {
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uint16_t value = adc_read(0); // Read from ADC0 (A0)
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int_to_hex_string(value, buffer, 2);
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uart_printstr_endl(buffer);
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_delay_ms(20); // Wait 20ms
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}
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}
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// ISR(ADC_vect) { // Table 12-6 : interrupt vector for ADC Conversion Complete
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// }
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