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/* -*- c++ -*- */

/* $Id: timer.c 395 2011-07-17 22:02:55Z mueller $ */

/*-----------------------------------------------------------------------------

 * Timer handling for FX2

 *-----------------------------------------------------------------------------

 * Code taken from USRP2 firmware (GNU Radio Project), version 3.0.2,

 * Copyright 2003 Free Software Foundation, Inc.

 *-----------------------------------------------------------------------------

 * This code is part of usbjtag. usbjtag 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 of the License,

 * or (at your option) any later version. usbjtag 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 this program in the file

 * COPYING; if not, write to the Free Software Foundation, Inc., 51 Franklin

 * St, Fifth Floor, 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 & 0xFF;

  T2CON = 0x04;                 // interrupt on overflow; reload; run

  ET2 = 1;                      // enable timer 2 interrupts

}