* Improve uart dma ring buffer. Sending dma still missing

* Add digio module for controlling LEDs, Loudspeaker, and the Digital IOs
* General code improvements

stm-firmware/syscalls.c

@@ -36,6 +36,6 @@ int _read(void) {
 	return 0;
 }
 int _write(int fd, const void *buf, int count) {
-	sendString((char*)buf, count);
+	uart_send_array((char*)buf, count);
 	return count;
 }