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authorJosh Blum <josh@joshknows.com>2010-11-05 19:55:19 -0700
committerJosh Blum <josh@joshknows.com>2010-11-05 19:55:19 -0700
commit13d735c65e40af23f978f96b5b418712976ab5f2 (patch)
tree020be6fd66df9a9d8ed9f328fa7c50713b6daa71 /firmware/fx2/common/timer.c
parent9d50dea1c2f884835b606ccaa1444e5de96926cb (diff)
parentf740a51cc0737b07fd4906f8ca80683ec6e87faa (diff)
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Merge branch 'mb_eeprom'
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
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+++ b/firmware/fx2/common/timer.c
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+/* -*- 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
+}