From ce92a90e58657ae14f291a75b00bd0391a9a89ff Mon Sep 17 00:00:00 2001 From: maralvira Date: Mon, 17 Jan 2011 15:51:19 +0000 Subject: [PATCH] new timer setup routines. --- cpu/mc1322x/lib/tmr.c | 97 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 97 insertions(+) create mode 100644 cpu/mc1322x/lib/tmr.c diff --git a/cpu/mc1322x/lib/tmr.c b/cpu/mc1322x/lib/tmr.c new file mode 100644 index 000000000..e2cc2afb6 --- /dev/null +++ b/cpu/mc1322x/lib/tmr.c @@ -0,0 +1,97 @@ +/* + * Copyright (c) 2010, Mariano Alvira and other contributors + * to the MC1322x project (http://mc1322x.devl.org) + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of the Institute nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * This file is part of libmc1322x: see http://mc1322x.devl.org + * for details. + * + * $Id: tmr.c,v 1.1 2011/01/17 15:51:19 maralvira Exp $ + */ + +#include +#include +#include "tmr.h" + +/* Initialize timer. This just counts and interrupts, doesn't drive an output. + timer_num = 0, 1, 2, 3 + rate = desired rate in Hz, + enable_int = whether to enable an interrupt on every cycle + Returns actual timer rate. */ +uint32_t timer_setup_ex(int timer_num, uint32_t rate, int enable_int) +{ + uint32_t actual_rate; + volatile struct TMR_struct *timer = TMR_ADDR(timer_num); + int log_divisor = 0; + uint32_t period; + + /* Turn timer off */ + TMR0->ENBL &= ~(1 << timer_num); + + /* Calculate optimal rate */ + for (log_divisor = 0; log_divisor < 8; log_divisor++) + { + int denom = (rate * (1 << log_divisor)); + period = (REF_OSC + denom/2) / denom; + if (period <= 65535) + break; + } + if (log_divisor >= 8) + { + period = 65535; + log_divisor = 7; + } + + if (period < 2) period = 2; + + actual_rate = REF_OSC / (period * (1 << log_divisor)); + + /* Set up timer */ + + timer->LOAD = 0; + timer->CMPLD1 = (period - 1); + timer->COMP1 = timer->CMPLD1; + timer->CNTR = timer->LOAD; + timer->SCTRL = 0; + timer->CSCTRLbits = (struct TMR_CSCTRL) { + .CL1 = 0x01, // Reload COMP1 when COMP1 matches + }; + timer->CTRLbits = (struct TMR_CTRL) { + .COUNT_MODE = 1, // Count rising edge of primary source + .PRIMARY_CNT_SOURCE = 8 + log_divisor, // Peripheral clock divided by (divisor) + .LENGTH = 1, // At compare, reset to LOAD + }; + + TMR0->ENBL |= (1 << timer_num); + + if (enable_int) { + enable_irq(TMR); + timer->SCTRLbits.TCFIE = 1; + } + + return actual_rate; +}