refactored printIntegerInBase to work without a buffer + minor cleanup

print.c

@@ -40,25 +40,24 @@ void printPgmString(const char *s)
 		serial_write(c);
 }
 
+// Prints a single digit of any base up to 36. 0..9 prints as
+// '0'..'9' while 10..35 prints as 'a'..'z'
+void printDigit(uint8_t value) {
+	serial_write(value < 10 ?
+		'0' + value :
+		'a' + value - 10);
+}
+
 void printIntegerInBase(unsigned long n, unsigned long base)
 { 
-	unsigned char buf[8 * sizeof(long)]; // Assumes 8-bit chars. 
-	unsigned long i = 0;
-
 	if (n == 0) {
-		serial_write('0');
+    printDigit(0);
 		return;
 	} 
-
 	while (n > 0) {
-		buf[i++] = n % base;
+    printDigit(n % base);
 		n /= base;
 	}
-
-	for (; i > 0; i--)
-		serial_write(buf[i - 1] < 10 ?
-			'0' + buf[i - 1] :
-			'A' + buf[i - 1] - 10);
 }
 
 void printInteger(long n)

protocol.c

@@ -72,7 +72,7 @@ uint8_t protocol_execute_line(char *line) {
 void protocol_process()
 {
   char c;
-  while((c = serial_read()) != 0xff) 
+  while((c = serial_read()) != SERIAL_NO_DATA) 
   {
     if((char_counter > 0) && ((c == '\n') || (c == '\r'))) {  // Line is complete. Then execute!
       line[char_counter] = 0; // treminate string

serial.c

@@ -23,6 +23,7 @@
 
 #include <avr/interrupt.h>
 #include <avr/sleep.h>
+#include "serial.h"
 
 
 #ifdef __AVR_ATmega328P__
@@ -97,7 +98,7 @@ uint8_t serial_read()
 {
 	if (rx_buffer_head != rx_buffer_tail) {
 	  // Return magic number if no data pending
-		return 0xff;
+		return SERIAL_NO_DATA;
 	} else {
 		uint8_t data = rx_buffer[rx_buffer_tail];
 		rx_buffer_tail = (rx_buffer_tail + 1) % RX_BUFFER_SIZE;

serial.h

@@ -24,6 +24,8 @@
 #ifndef serial_h
 #define serial_h
 
+#define SERIAL_NO_DATA 0xff
+
 void serial_init(long baud);
 
 void serial_write(uint8_t data);