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authorJosh Blum <josh@joshknows.com>2010-11-05 21:22:54 -0700
committerJosh Blum <josh@joshknows.com>2010-11-05 21:22:54 -0700
commit374f6ff05e66d10830a7567d2d793de2bf77c06b (patch)
treeca170bd9473de690ffff45b2041cf10f83fb0228 /firmware/fx2/common/timer.c
parent92b5034cb5a6e17fe7ebc437f7ef26147d69eba3 (diff)
parentc2cc364f9fde9633e2d7c04fa5b07275e17ba093 (diff)
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Merge branch 'master' into flow_ctrl
Conflicts: host/lib/usrp/usrp2/mboard_impl.cpp host/lib/usrp/usrp2/usrp2_impl.hpp
Diffstat (limited to 'firmware/fx2/common/timer.c')
-rw-r--r--firmware/fx2/common/timer.c49
1 files changed, 49 insertions, 0 deletions
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
+}