feat(ex04): better control char handling and commenting unused functions

ex04/Makefile

@@ -12,7 +12,7 @@ SERIAL=-P /dev/ttyUSB0 -b 115200
 SRC_DIR=src
 OBJ_DIR=build
 
-SRC_FILES=main.c utils.c uart.c timer.c
+SRC_FILES=main.c utils.c uart.c
 OBJ_FILES=$(patsubst %.c,%.o,$(SRC_FILES))
 
 SRC=$(addprefix $(SRC_DIR)/,$(SRC_FILES))

ex04/src/main.c

@@ -94,6 +94,10 @@ int main(void) {
 					}
 					continue;
 				}
+
+				// this is a control char -> we dont want it !
+				if (data < ' ' || data > '~')
+					continue;
 				uart_tx(data);
 
 				if (cursor + 1 >= BUFFERSIZE) {
@@ -119,6 +123,9 @@ int main(void) {
 					}
 					continue;
 				}
+				// this is a control char -> we dont want it !
+				if (data < ' ' || data > '~')
+					continue;
 				uart_tx('*');
 
 				if (cursor + 1 >= BUFFERSIZE) {

ex04/src/timer.c

@@ -1,38 +0,0 @@
-
-#include <avr/io.h>
-#include <avr/interrupt.h>
-#include "mystd.h"
-#include "utils.h"
-
-#define PRESCALER 256
-#define TIMER_FREQ (F_CPU / PRESCALER)
-
-// at a high level:
-// Set the OC1B (PB2) pin as output
-// set the TIMER1 mode to COMPARE (CTC)
-// say to compare against OC1A
-// set the value to be compated at X count
-// say the presacler for the timer is 512
-//
-// all these information are on page ~140
-void timer1_init(void) {
-	// Set PB1 (OC1A) as output
-	DDRB   |= _BV(PB1);
-
-	// CTC mode (WGM12 = 1)
-	TCCR1B |= _BV(WGM12);
-
-	// Toggle OC1B on compare match (COM1B0 = 1)
-	// TCCR1A |= _BV(COM1A0);
-
-	// Set compare values
-	OCR1A	= TIMER_FREQ / 2;
-
-	// Start timer with prescaler 256 (CS12)
-	TCCR1B |= _BV(CS12);
-	
-	// set OCR1A interrupt
-	TIMSK1 = _BV(1);
-
-	sei();
-}

ex04/src/uart.c

@@ -47,7 +47,7 @@ void uart_sendstring(const char* str) {
 		str++;
 	}
 }
-
+/*
 void uart_send_u8(uint8_t val) {
 	char	buf[4]	= {0, 0, 0, 0};
 	uint8_t idx		= 0;
@@ -102,3 +102,4 @@ void uart_send_u16_hex(uint16_t val) {
 	buf[3]		   = "0123456789abcdef"[(val >> 0) & 0x0F];
 	uart_sendstring(buf);
 }
+*/