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gnss-sdr/firmware/GN3S_v2/lib/timer.c
Javier Arribas b849b20a8c Added optional support for Sparkfun SiGe GN3S USB GPS RF sampler:
- Added a pre-compiled custom GN3S firmware.
- Added a fully-compliant GNU Radio source block for GN3S USB dongle. It can be used also from GNU Radio companion and from Python applications.
- Added a new GN3S_Signal_Source block. It is possible to disable the GN3S signal source compilation. See README.

git-svn-id: https://svn.code.sf.net/p/gnss-sdr/code/trunk@217 64b25241-fba3-4117-9849-534c7e92360d
2012-07-30 15:46:07 +00:00

50 lines
1.5 KiB
C

/* -*- 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
}