convert hex str to color

module03/ex03/main.c

@@ -5,22 +5,13 @@
 #include "utils.h"
 #include "bitmanip.h"
 
+// prototypes
 void init_rgb();
-
 void set_rgb(uint8_t r, uint8_t g, uint8_t b);
-
-void wheel(uint8_t pos) {
-	pos = 255 - pos;
-	if (pos < 85) {
-		set_rgb(255 - pos * 3, 0, pos * 3);
-	} else if (pos < 170) {
-		pos = pos - 85;
-		set_rgb(0, pos * 3, 255 - pos * 3);
-	} else {
-		pos = pos - 170;
-		set_rgb(pos * 3, 255 - pos * 3, 0);
-	}
-}
+uint8_t get_red(char *input);
+uint8_t get_green(char *input);
+uint8_t get_blue(char *input);
+uint8_t hex_to_int(char c);
 
 // Table 14-9 : Port D Pins Alternate Functions
 // OC2B (PD3) : Red
@@ -56,14 +47,48 @@ void set_rgb(uint8_t r, uint8_t g, uint8_t b) {
     OCR0A = b;											// Blue (PD6, Timer0 OCR0A)
 }
 
+// convert hex to int : https://stackoverflow.com/a/39052987
+uint8_t hex_to_int(char c) {
+	if (c >= '0' && c <= '9') {
+		return c - '0';
+	}
+	if (c >= 'A' && c <= 'F') {
+		return c - 'A' + 10;
+	}
+	if (c >= 'a' && c <= 'f') {
+		return c - 'a' + 10;
+	}
+	return 0;
+}
+
+// "<< 4" is equivalent to "* 16"
+uint8_t get_red(char *input) {
+	if (input[0] == '#') {
+		return (hex_to_int(input[1]) << 4) + hex_to_int(input[2]);
+	}
+	return 0;
+}
+uint8_t get_green(char *input) {
+	if (input[0] == '#') {
+		return (hex_to_int(input[3]) << 4) + hex_to_int(input[4]);
+	}
+	return 0;
+}
+uint8_t get_blue(char *input) {
+	if (input[0] == '#') {
+		return (hex_to_int(input[5]) << 4) + hex_to_int(input[6]);
+	}
+	return 0;
+}
+
 // led RGB D5 must turns on in a loop of colors using PWM
 int main() {
 	init_rgb();
 
-    uint8_t pos = 0;
-    while (1) {
-        wheel(pos);										// Set color based on wheel position
-        _delay_ms(10);									// Small delay for smooth transition
-        pos++;											// Increment color position
-    }
+	char *input = "#FFFF00";
+	uint8_t r = get_red(input);
+	uint8_t g = get_green(input);
+	uint8_t b = get_blue(input);
+	set_rgb(r, g, b);
+    while (1);
 }