/* SPDX-License-Identifier: BSD-2-Clause */
/**
* @file
*
* @ingroup RTEMSBSPsARMLPC176X_clocks
*
* @brief System clocks.
*/
/*
* Copyright (c) 2008-2012 embedded brains GmbH. 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.
*
* 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 OWNER 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.
*/
#include <bsp.h>
#include <bsp/system-clocks.h>
/**
* @brief Internal RC oscillator frequency in [Hz].
*/
#define LPC176X_OSCILLATOR_INTERNAL 4000000u
#ifndef LPC176X_OSCILLATOR_MAIN
#error "unknown main oscillator frequency"
#endif
#ifndef LPC176X_OSCILLATOR_RTC
#error "unknown RTC oscillator frequency"
#endif
inline unsigned lpc176x_sysclk( void );
void lpc176x_timer_initialize( void )
{
/* Reset timer */
LPC176X_T1TCR = TCR_RST;
/* Set timer mode */
LPC176X_T1CTCR = 0u;
/* Set prescaler to zero */
LPC176X_T1PR = 0u;
/* Reset all interrupt flags */
LPC176X_T1IR = 0xffU;
/* Do not stop on a match */
LPC176X_T1MCR = 0u;
/* No captures */
LPC176X_T1CCR = 0u;
/* Start timer */
LPC176X_T1TCR = TCR_EN;
}
void lpc176x_micro_seconds_delay( const unsigned us )
{
const unsigned start = lpc176x_get_timer1();
const unsigned delay = us * ( LPC176X_PCLK / 1000000u );
unsigned elapsed = 0u;
do {
elapsed = lpc176x_get_timer1() - start;
} while ( elapsed < delay );
}
unsigned lpc176x_sysclk( void )
{
return ( LPC176X_SCB.clksrcsel & LPC176X_SCB_CLKSRCSEL_CLKSRC ) != 0u ?
LPC176X_OSCILLATOR_MAIN : LPC176X_OSCILLATOR_INTERNAL;
}
unsigned lpc176x_pllclk( void )
{
const unsigned sysclk = lpc176x_sysclk();
const unsigned pllstat = ( LPC176X_SCB.pll_0 ).stat;
const unsigned enabled_and_locked = LPC176X_PLL_STAT_PLLE |
LPC176X_PLL_STAT_PLOCK;
unsigned pllclk = 0u;
if ( ( pllstat & enabled_and_locked ) == enabled_and_locked ) {
unsigned m = LPC176X_PLL_SEL_MSEL_GET( pllstat ) + 1u;
pllclk = sysclk * m;
}
/* else implies that the pllstat is unlocked. Also,
there is nothing to do. */
return pllclk;
}
unsigned lpc176x_cclk( void )
{
const unsigned cclksel = LPC176X_SCB.cclksel;
unsigned cclk_in = 0u;
unsigned cclk = 0u;
if ( ( cclksel & LPC176X_SCB_CCLKSEL_CCLKSEL ) != 0u ) {
cclk_in = lpc176x_pllclk();
} else {
cclk_in = lpc176x_sysclk();
}
cclk = cclk_in / LPC176X_SCB_CCLKSEL_CCLKDIV_GET( cclksel );
return cclk;
}
uint32_t _CPU_Counter_frequency(void)
{
return LPC176X_PCLK;
}
CPU_Counter_ticks _CPU_Counter_read( void )
{
return lpc176x_get_timer1();
}
