Houston, we have a trunk.

git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@3122 221aa14e-8319-0410-a670-987f0aec2ac5

1 files changed, 49 insertions, 0 deletions

diff --git a/usrp/firmware/lib/timer.c b/usrp/firmware/lib/timer.c
new file mode 100644
index 000000000..9e396f469
--- /dev/null
+++ b/usrp/firmware/lib/timer.c
@@ -0,0 +1,49 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2003 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include "timer.h"
+#include "fx2regs.h"
+#include "isr.h"
+
+/*
+ * Arrange to have isr_tick_handler called at 100 Hz.
+ *
+ * The cpu clock is running at 48e6.  The input to the timer
+ * is 48e6 / 12 = 4e6.
+ *
+ * We arrange to have the timer overflow every 40000 clocks == 100 Hz
+ */
+
+#define	RELOAD_VALUE	((unsigned short) -40000)
+
+void 
+hook_timer_tick (unsigned short isr_tick_handler)
+{
+  ET2 = 0;			// disable timer 2 interrupts
+  hook_sv (SV_TIMER_2, isr_tick_handler);
+  
+  RCAP2H = RELOAD_VALUE >> 8;	// setup the auto reload value
+  RCAP2L = RELOAD_VALUE;
+
+  T2CON = 0x04;			// interrupt on overflow; reload; run
+  ET2 = 1;			// enable timer 2 interrupts
+}