nes-proj/cpu/cc26xx/clock.c

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2015-02-25 12:09:56 +00:00
/*
* Copyright (c) 2014, Texas Instruments Incorporated - http://www.ti.com/
* 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 copyright holder 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 COPYRIGHT HOLDERS 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
* COPYRIGHT HOLDER 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.
*/
/*---------------------------------------------------------------------------*/
/**
* \addtogroup platform
* @{
*
* \defgroup cc26xx-platforms TI CC26xx-powered Platforms
* @{
*
* \defgroup cc26xx The TI CC26xx CPU
* @{
*
* \addtogroup cc26xx-clocks
* @{
*
* \defgroup cc26xx-software-clock CC26xx Software Clock
*
* Implementation of the clock module for the cc26xx.
*
* The software clock uses the facilities provided by the AON RTC driver
* @{
*
* \file
* Software clock implementation for the TI CC26xx
*/
/*---------------------------------------------------------------------------*/
#include "contiki.h"
#include "ti-lib.h"
/*---------------------------------------------------------------------------*/
static volatile clock_time_t count;
static volatile clock_time_t second_countdown;
static volatile unsigned long secs;
/*---------------------------------------------------------------------------*/
static void
power_domain_on(void)
{
ti_lib_prcm_power_domain_on(PRCM_DOMAIN_PERIPH);
while(ti_lib_prcm_power_domain_status(PRCM_DOMAIN_PERIPH) !=
PRCM_DOMAIN_POWER_ON);
}
/*---------------------------------------------------------------------------*/
void
clock_init(void)
{
count = 0;
secs = 0;
second_countdown = CLOCK_SECOND;
/*
* Here, we configure GPT0 Timer A, which we subsequently use in
* clock_delay_usec
*
* First, enable GPT0 in run mode. We don't need it in sleep mode
*/
ti_lib_prcm_peripheral_run_enable(PRCM_PERIPH_TIMER0);
ti_lib_prcm_load_set();
while(!ti_lib_prcm_load_get());
/* Disable both GPT0 timers */
HWREG(GPT0_BASE + GPT_O_CTL) &= ~(GPT_CTL_TAEN | GPT_CTL_TBEN);
/*
* We assume that the clock is running at 48MHz, we use GPT0 Timer A,
* one-shot, countdown, prescaled by 48 gives us 1 tick per usec
*/
ti_lib_timer_configure(GPT0_BASE,
TIMER_CFG_SPLIT_PAIR | TIMER_CFG_B_ONE_SHOT);
/* Global config: split pair (2 x 16-bit wide) */
HWREG(GPT0_BASE + GPT_O_CFG) = TIMER_CFG_SPLIT_PAIR >> 24;
/*
* Pre-scale value 47 pre-scales by 48
*
* ToDo: The theoretical value here should be 47 (to provide x48 prescale)
* However, 49 seems to give results much closer to the desired delay
*/
ti_lib_timer_prescale_set(GPT0_BASE, TIMER_B, 49);
/* GPT0 / Timer B: One shot, PWM interrupt enable */
HWREG(GPT0_BASE + GPT_O_TBMR) =
((TIMER_CFG_B_ONE_SHOT >> 8) & 0xFF) | GPT_TBMR_TBPWMIE;
}
/*---------------------------------------------------------------------------*/
CCIF clock_time_t
clock_time(void)
{
return count;
}
/*---------------------------------------------------------------------------*/
void
clock_update(void)
{
count++;
if(etimer_pending()) {
etimer_request_poll();
}
if(--second_countdown == 0) {
secs++;
second_countdown = CLOCK_SECOND;
}
}
/*---------------------------------------------------------------------------*/
void
clock_set_seconds(unsigned long sec)
{
secs = sec;
}
/*---------------------------------------------------------------------------*/
CCIF unsigned long
clock_seconds(void)
{
return secs;
}
/*---------------------------------------------------------------------------*/
void
clock_wait(clock_time_t i)
{
clock_time_t start;
start = clock_time();
while(clock_time() - start < (clock_time_t)i);
}
/*---------------------------------------------------------------------------*/
void
clock_delay_usec(uint16_t len)
{
if(ti_lib_prcm_power_domain_status(PRCM_DOMAIN_PERIPH) !=
PRCM_DOMAIN_POWER_ON) {
power_domain_on();
}
ti_lib_timer_load_set(GPT0_BASE, TIMER_B, len);
ti_lib_timer_enable(GPT0_BASE, TIMER_B);
/*
* Wait for TBEN to clear. CC26xxware does not provide us with a convenient
* function, hence the direct register access here
*/
while(HWREG(GPT0_BASE + GPT_O_CTL) & GPT_CTL_TBEN);
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}
/*---------------------------------------------------------------------------*/
/**
* \brief Obsolete delay function but we implement it here since some code
* still uses it
*/
void
clock_delay(unsigned int i)
{
clock_delay_usec(i);
}
/*---------------------------------------------------------------------------*/
/**
* @}
* @}
* @}
* @}
* @}
*/