first version m05e00

module05/ex00/main.c

@@ -1,6 +1,56 @@
 #include "header.h"
 
+// Table 14-6. Port C Pins Alternate Functions
+// - PC0 -> ADC0 (ADC Input Channel 0)
+//       -> PCINT8 (Pin Change Interrupt 8)
+//
+// 24.2 : The ADC generates a 10-bit result which is presented in the ADC Data Registers, ADCH and ADCL
+
+#define INT_TO_HEX_CHAR(n) ((n) < 10 ? ('0' + (n)) : ('A' + ((n) - 10)))
+void int_to_hex_string(uint64_t value, char *out, uint8_t num_digits) {
+    for (uint8_t i = 0; i < num_digits; ++i) {
+        uint8_t shift = (num_digits - 1 - i) * 4;
+        out[i] = INT_TO_HEX_CHAR((value >> shift) & 0x0F);
+    }
+    out[num_digits] = '\0';
+}
+void word_to_hex(uint16_t value, char *out) {
+    out[0] = INT_TO_HEX_CHAR((value >> 8) & 0x0F);
+    out[1] = INT_TO_HEX_CHAR((value >> 4) & 0x0F);
+    out[2] = INT_TO_HEX_CHAR(value & 0x0F);
+    out[3] = '\0';
+}
+
+void adc_init() {
+    ADMUX = (1 << REFS0); // AVcc reference, ADC0
+    ADCSRA = (1 << ADEN)  // Enable ADC
+           | (1 << ADPS2) | (1 << ADPS1) | (1 << ADPS0); // Prescaler = 128
+}
+
+uint16_t adc_read(uint8_t channel) {
+    ADMUX = (ADMUX & 0xF0) | (channel & 0x0F);  // Select ADC channel
+    ADCSRA |= (1 << ADSC);                     // Start conversion
+    while (ADCSRA & (1 << ADSC));              // Wait for completion
+    return ADC;
+}
+
 // description
 int main() {
-	while(1);
+    char buffer[4];
+	SREG |= ENABLE_GLOBAL_INTERRUPT;												// 7.3.1 : Status Register, bit 7 : I – Global Interrupt Enable
+	uart_init();
+
+	adc_init();
+
+	while(1) {
+        uint16_t value = adc_read(0); // Read from ADC0 (A0)
+        // snprintf(buffer, sizeof(buffer), "ADC: %u\r\n", value);
+		word_to_hex(value, buffer);
+        uart_printstr(buffer);
+        uart_printstr("\r\n");
+        _delay_ms(20); // Wait 20ms
+	}
 }
+
+// ISR(ADC_vect) {		// Table 12-6 : interrupt vector for ADC Conversion Complete
+// }