successfully maintained 30khz, lots of optimization of code and buffering allocation

wiring_serial.c

@@ -28,7 +28,7 @@
 // using a ring buffer (I think), in which rx_buffer_head is the index of the
 // location to which to write the next incoming character and rx_buffer_tail
 // is the index of the location from which to read.
-#define RX_BUFFER_SIZE 256
+#define RX_BUFFER_SIZE 200
 
 unsigned char rx_buffer[RX_BUFFER_SIZE];