From 2b1aff2adeb930e1be791837678ae278b9a0e1f0 Mon Sep 17 00:00:00 2001
From: Richard Meadows <richardeoin@gmail.com>
Date: Thu, 2 Apr 2015 20:57:25 +0100
Subject: [PATCH] Option for not using external oscillator

---
 firmware/inc/hw_config.h | 1 +
 firmware/src/xosc.c      | 6 ++++++
 2 files changed, 7 insertions(+)

diff --git a/firmware/inc/hw_config.h b/firmware/inc/hw_config.h
index 576daa1..ee7a160 100644
--- a/firmware/inc/hw_config.h
+++ b/firmware/inc/hw_config.h
@@ -121,6 +121,7 @@
 /**
  * XOSC
  */
+//define USE_XOSC
 #define XOSC_FREQUENCY		16369000
 #define XOSC_GCLK1_DIVIDE	4
 
diff --git a/firmware/src/xosc.c b/firmware/src/xosc.c
index ed55de2..72828c6 100644
--- a/firmware/src/xosc.c
+++ b/firmware/src/xosc.c
@@ -48,6 +48,7 @@ measurement_result_t _callback;
  * connects it to GLCK1.
  */
 void xosc_init(void) {
+#ifdef USE_XOSC
   system_clock_source_xosc_set_config(SYSTEM_CLOCK_EXTERNAL_CLOCK,
                                       SYSTEM_XOSC_STARTUP_1,
                                       true,
@@ -57,10 +58,15 @@ void xosc_init(void) {
   system_clock_source_enable(SYSTEM_CLOCK_SOURCE_XOSC);
 
   while (!system_clock_source_is_ready(SYSTEM_CLOCK_SOURCE_XOSC));
+#endif
 
   /* Configure GCLK1 to XOSC */
   system_gclk_gen_set_config(GCLK_GENERATOR_1,
+#ifdef USE_XOSC
         		     GCLK_SOURCE_XOSC, /* Source 		*/
+#else
+                             GCLK_SOURCE_OSC8M, /* Source 		*/
+#endif
         		     false,		/* High When Disabled	*/
         		     XOSC_GCLK1_DIVIDE,/* Division Factor	*/
         		     false,		/* Run in standby	*/