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/**
* @file
*
* @ingroup lpc24xx_clocks
*
* @brief System clocks.
*/
/*
* Copyright (c) 2008
* Embedded Brains GmbH
* Obere Lagerstr. 30
* D-82178 Puchheim
* Germany
* rtems@embedded-brains.de
*
* The license and distribution terms for this file may be found in the file
* LICENSE in this distribution or at http://www.rtems.com/license/LICENSE.
*/
#include <bsp.h>
#include <bsp/utility.h>
#include <bsp/lpc24xx.h>
#include <bsp/system-clocks.h>
/**
* @brief Internal RC oscillator frequency in [Hz].
*/
#define LPC24XX_OSCILLATOR_INTERNAL 4000000U
#ifndef LPC24XX_OSCILLATOR_MAIN
#error "unknown main oscillator frequency"
#endif
#ifndef LPC24XX_OSCILLATOR_RTC
#error "unknown RTC oscillator frequency"
#endif
void lpc24xx_timer_initialize(void)
{
/* Reset timer */
T1TCR = TCR_RST;
/* Set timer mode */
T1CTCR = 0;
/* Set prescaler to zero */
T1PR = 0;
/* Reset all interrupt flags */
T1IR = 0xff;
/* Do not stop on a match */
T1MCR = 0;
/* No captures */
T1CCR = 0;
/* Start timer */
T1TCR = TCR_EN;
}
void lpc24xx_micro_seconds_delay(unsigned us)
{
unsigned start = lpc24xx_timer();
unsigned end = start + us * (lpc24xx_cclk() / 1000000);
unsigned now = 0;
do {
now = lpc24xx_timer();
} while (now < end);
}
unsigned lpc24xx_pllclk(void)
{
unsigned clksrc = GET_CLKSRCSEL_CLKSRC(CLKSRCSEL);
unsigned pllinclk = 0;
unsigned pllclk = 0;
/* Get PLL input frequency */
switch (clksrc) {
case 0:
pllinclk = LPC24XX_OSCILLATOR_INTERNAL;
break;
case 1:
pllinclk = LPC24XX_OSCILLATOR_MAIN;
break;
case 2:
pllinclk = LPC24XX_OSCILLATOR_RTC;
break;
default:
return 0;
}
/* Get PLL output frequency */
if (IS_FLAG_SET(PLLSTAT, PLLSTAT_PLLC)) {
uint32_t pllcfg = PLLCFG;
unsigned n = GET_PLLCFG_NSEL(pllcfg) + 1;
unsigned m = GET_PLLCFG_MSEL(pllcfg) + 1;
pllclk = (pllinclk / n) * 2 * m;
} else {
pllclk = pllinclk;
}
return pllclk;
}
unsigned lpc24xx_cclk(void)
{
/* Get PLL output frequency */
unsigned pllclk = lpc24xx_pllclk();
/* Get CPU frequency */
unsigned cclk = pllclk / (GET_CCLKCFG_CCLKSEL(CCLKCFG) + 1);
return cclk;
}
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