updated example in readme for new interface

README.md

@@ -29,13 +29,28 @@ likely end up being the end result.
 ```C
 #include "avr_usart.h"
 
-void send_bt_cmd(char* cmd) {
+/*
+ *Description: Echos a single char back to the term.
+ */
+void echo_char(char* cmd) {
     init_usart();
-    unsigned char data[] = "AT+WAKE\0";
-    uint8_t result = usart_send_str(data);
     
-    if(result) {
-        raise_error();
+    unsigned char data[1] = "0";
+    uint8_t data_len = 1;
+
+    //clear the buffer
+    serial0_flush_rxbuf();
+
+    //receive the char.
+    serial0_read(data, data_len);
+
+    //Now echo it.
+    serial0_write(data, data_len);
+}
+
+int main() {
+    while(1) {
+        echo_char();
     }
 }