wip commenting

.vscode/settings.json

@@ -9,6 +9,7 @@
     "bitmanip.h": "c",
     "rush_header.h": "c",
     "twi.h": "c",
-    "header.h": "c"
+    "header.h": "c",
+    "adc.h": "c"
   }
 }

headers/utils.h

@@ -12,6 +12,7 @@
 // mathematics
 #define PERCENT(percent, total)		(((float)percent / 100) * total)
 #define DIV_ROUND_CLOSEST(n, d)		((((n) < 0) == ((d) < 0)) ? (((n) + (d)/2)/(d)) : (((n) - (d)/2)/(d)))
+#define INT_TO_HEX_CHAR(n)			((n) < 10 ? ('0' + (n)) : ('A' + ((n) - 10)))
 
 // text
 #define SWITCH_CASE(ch)				(((ch) >= 'A' && (ch) <= 'Z') || ((ch) >= 'a' && (ch) <= 'z') ? ((ch) ^ (1 << 5)) : (ch))

module05/ex00/adc.c

@@ -0,0 +1,27 @@
+#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
+//
+// START A CONVERSTION in single conversion mode :
+// - disabling the Power Reduction ADC bit, PRADC
+// - writing a logical one to the ADC Start Conversion bit, ADSC
+
+#define ADC_PRESCALER	8
+
+void adc_init() {
+    ADMUX = (1 << REFS0);						// Table 24-3 : set voltage reference, AVCC with external capacitor at AREF pin
+    ADCSRA = (1 << ADEN) 						// 24.9.2 : enable ADC
+           | ADC_PRESCALE_SET(ADC_PRESCALER);	// Table 24-5 : prescaler ADC
+}
+
+uint16_t adc_read(uint8_t channel) {
+	CLEAR(PRR, PRADC);							// 24.3 : ensure power reduction is disabled for ADC, (10.11.3 : PRR – Power Reduction Register)
+    ADMUX = (ADMUX & 0xF0) | (channel & 0x0F);	// Select ADC channel
+    ADCSRA |= (1 << ADSC);						// 24.9.2 : Start conversion, ADSC: ADC Start Conversion
+    while (ADCSRA & (1 << ADSC));				// Wait for completion
+    return ADC;
+}

module05/ex00/adc.h

@@ -0,0 +1,15 @@
+#ifndef ADC_H
+#define ADC_H
+
+// Table 24-5 : prescaler ADC
+#define ADC_PRESCALE_SET(value)  \
+									((value) == 2   ? (0<<ADPS2 | 0<<ADPS1 | 1<<ADPS0) : \
+									 (value) == 4   ? (0<<ADPS2 | 1<<ADPS1 | 0<<ADPS0) : \
+									 (value) == 8   ? (0<<ADPS2 | 1<<ADPS1 | 1<<ADPS0) : \
+									 (value) == 16  ? (1<<ADPS2 | 0<<ADPS1 | 0<<ADPS0) : \
+									 (value) == 32  ? (1<<ADPS2 | 0<<ADPS1 | 1<<ADPS0) : \
+									 (value) == 64  ? (1<<ADPS2 | 1<<ADPS1 | 0<<ADPS0) : \
+									 (value) == 128 ? (1<<ADPS2 | 1<<ADPS1 | 1<<ADPS0) : \
+													  (0<<ADPS2 | 0<<ADPS1 | 0<<ADPS0))
+
+#endif // ADC_H

module05/ex00/header.h

@@ -10,15 +10,21 @@
 #include "interrupt.h"
 #include "timer.h"
 #include "usart.h"
+#include "adc.h"
 
 //
 // PROTOTYPES
 //
 // main.c
+void int_to_hex_string(uint64_t value, char *out, uint8_t num_digits);
+// adc.c
+void adc_init();
+uint16_t adc_read(uint8_t channel);
 // uart.c
 void uart_init();
 void uart_tx(char c);
 void uart_printstr(const char* str);
+void uart_printstr_endl(const char* str) 
 
 //
 // MACROS

module05/ex00/main.c

@@ -1,12 +1,5 @@
 #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;
@@ -14,40 +7,18 @@ void int_to_hex_string(uint64_t value, char *out, uint8_t num_digits) {
     }
     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() {
-    char buffer[4];
+    const 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);
+		int_to_hex_string(value, buffer, 3);
-		word_to_hex(value, buffer);
+        uart_printstr_endl(buffer);
-        uart_printstr(buffer);
-        uart_printstr("\r\n");
         _delay_ms(20);																// Wait 20ms
 	}
 }

module05/ex00/uart.c

@@ -34,6 +34,11 @@ void uart_printstr(const char* str) {
 	}
 }
 
+void uart_printstr_endl(const char* str) {
+	uart_printstr(str);
+	uart_printstr("\r\n");
+}
+
 // ISR(USART_RX_vect) {																// Table 12-6 : we select the code for USART Receive
 // 	char received_char = UDR0;														// read received character
 // 	if (received_char == '\b' || received_char == 127) {							// if backspace is received