From c473cc56fafcb47d6ba1f16e8c9fb89ff6c57bca Mon Sep 17 00:00:00 2001
From: Josh Blum <josh@joshknows.com>
Date: Fri, 5 Nov 2010 12:32:09 -0700
Subject: usrp1: pulled in cmake build system for usrp1 firmware

---
 firmware/fx2/common/timer.c | 49 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)
 create mode 100644 firmware/fx2/common/timer.c

(limited to 'firmware/fx2/common/timer.c')

diff --git a/firmware/fx2/common/timer.c b/firmware/fx2/common/timer.c
new file mode 100644
index 000000000..97e2f7cf9
--- /dev/null
+++ b/firmware/fx2/common/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 3, 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., 51 Franklin Street,
+ * Boston, MA 02110-1301, 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
+}
-- 
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