working on serial syncronization for programming eeprom

1 files changed, 14 insertions, 4 deletions

diff --git a/src/uart.c b/src/uart.c
index 3ba75db..ca1e587 100644
--- a/src/uart.c
+++ b/src/uart.c
@@ -1,6 +1,7 @@
 #include <avr/io.h>
 #include <stdio.h>
 #include <util/setbaud.h>
+#include "pins.h"
 
 /** UART notes
  * UCSR0A:
@@ -35,27 +36,36 @@
  * ____________________________________________________________
  * UBRR0(H,L): baudrates
  *
+ *
  **/
 
 //TODO replace with static void and just use high level functions?
 void uart_sendbyte(uint8_t byte) { 
-  if(byte == '\n') uart_sendbyte('\r');
-  loop_until_bit_is_set(UCSR0A, UDRE0); 
+  UART_PORT &= ~(_BV(UART_RTS)); //us: ready to send
+  loop_until_bit_is_clear(UART_PORT, UART_CTS); //them: go ahead
+  //also wait for buffer to be empty, should never be a problem
+  loop_until_bit_is_set(UCSR0A, UDRE0); //done recieving
   UDR0 = byte; 
+  UART_PORT |= _BV(UART_RTS); //keep in mind cts is inverted; low is 1 and high is 0
 }
 
 //TODO replace with static void and just use high level functions?
 uint8_t uart_recvbyte() {
-  loop_until_bit_is_set(UCSR0A, RXC0);
+  loop_until_bit_is_clear(UART_PORT, UART_CTS); //wait for their request
+  UART_PORT &= ~(_BV(UART_RTS)); //hey, you can send now
+  loop_until_bit_is_set(UCSR0A, RXC0); //wait for them to actually send
+  UART_PORT |= _BV(UART_RTS); //okay, you can no longer send
   return UDR0;
 }
 
 void uart_init() {
   //set baud rate
+  UART_DDR |= _BV(UART_RTS); 
+  UART_PORT |= _BV(UART_RTS); //keep in mind cts is inverted; low is 1 and high is 0
+
   UBRR0H = UBRRH_VALUE;
   UBRR0L = UBRRL_VALUE;
 
-
 /**
 TODO figure out why USE_2X is enable when it shoudn't be
    //set baud rate