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system_LPC8xx.c
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174 lines (155 loc) · 6.78 KB
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/******************************************************************************
* @file: system_LPC8xx.c
* @purpose: CMSIS Cortex-M0+ Device Peripheral Access Layer Source File
* for the NXP LPC8xx Device Series
* @version: V1.0
* @date: 16. Aug. 2012
*----------------------------------------------------------------------------
*
* Copyright (C) 2012 ARM Limited. All rights reserved.
*
* ARM Limited (ARM) is supplying this software for use with Cortex-M0+
* processor based microcontrollers. This file can be freely distributed
* within development tools that are supporting such ARM based processors.
*
* THIS SOFTWARE IS PROVIDED "AS IS". NO WARRANTIES, WHETHER EXPRESS, IMPLIED
* OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE.
* ARM SHALL NOT, IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR
* CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER.
*
******************************************************************************/
#include <stdint.h>
#include "LPC8xx.h"
#include "system_LPC8xx.h"
/*----------------------------------------------------------------------------
Clock Variable definitions
*----------------------------------------------------------------------------*/
uint32_t SystemCoreClock = __SYSTEM_CLOCK;/*!< System Clock Frequency (Core Clock)*/
/*----------------------------------------------------------------------------
Clock functions
*----------------------------------------------------------------------------*/
void SystemCoreClockUpdate (void) /* Get Core Clock Frequency */
{
uint32_t wdt_osc = 0;
/* Determine clock frequency according to clock register values */
switch ((LPC_SYSCON->WDTOSCCTRL >> 5) & 0x0F) {
case 0: wdt_osc = 0; break;
case 1: wdt_osc = 500000; break;
case 2: wdt_osc = 800000; break;
case 3: wdt_osc = 1100000; break;
case 4: wdt_osc = 1400000; break;
case 5: wdt_osc = 1600000; break;
case 6: wdt_osc = 1800000; break;
case 7: wdt_osc = 2000000; break;
case 8: wdt_osc = 2200000; break;
case 9: wdt_osc = 2400000; break;
case 10: wdt_osc = 2600000; break;
case 11: wdt_osc = 2700000; break;
case 12: wdt_osc = 2900000; break;
case 13: wdt_osc = 3100000; break;
case 14: wdt_osc = 3200000; break;
case 15: wdt_osc = 3400000; break;
}
wdt_osc /= ((LPC_SYSCON->WDTOSCCTRL & 0x1F) << 1) + 2;
switch (LPC_SYSCON->MAINCLKSEL & 0x03) {
case 0: /* Internal RC oscillator */
SystemCoreClock = __IRC_OSC_CLK;
break;
case 1: /* Input Clock to System PLL */
switch (LPC_SYSCON->SYSPLLCLKSEL & 0x03) {
case 0: /* Internal RC oscillator */
SystemCoreClock = __IRC_OSC_CLK;
break;
case 1: /* System oscillator */
SystemCoreClock = __SYS_OSC_CLK;
break;
case 2: /* Reserved */
SystemCoreClock = 0;
break;
case 3: /* CLKIN pin */
SystemCoreClock = __CLKIN_CLK;
break;
}
break;
case 2: /* WDT Oscillator */
SystemCoreClock = wdt_osc;
break;
case 3: /* System PLL Clock Out */
switch (LPC_SYSCON->SYSPLLCLKSEL & 0x03) {
case 0: /* Internal RC oscillator */
SystemCoreClock = __IRC_OSC_CLK * ((LPC_SYSCON->SYSPLLCTRL & 0x01F) + 1);
break;
case 1: /* System oscillator */
SystemCoreClock = __SYS_OSC_CLK * ((LPC_SYSCON->SYSPLLCTRL & 0x01F) + 1);
break;
case 2: /* Reserved */
SystemCoreClock = 0;
break;
case 3: /* CLKIN pin */
SystemCoreClock = __CLKIN_CLK * ((LPC_SYSCON->SYSPLLCTRL & 0x01F) + 1);
break;
}
break;
}
SystemCoreClock /= LPC_SYSCON->SYSAHBCLKDIV;
}
// cpldcpu - added 2013/06/23
// Delays by 3*ticks cycles
__attribute__((always_inline))
static inline void __delayticks(unsigned int ticks) {
asm volatile(
"loop%=: sub %[ctr],#1 \n"
" bne loop%=\n"
: [ctr] "+r" (ticks)
);
}
/**
* Initialize the system
*
* @param none
* @return none
*
* @brief Setup the microcontroller system.
* Initialize the System.
*/
void SystemInit (void) {
/* System clock to the IOCON & the SWM need to be enabled or
most of the I/O related peripherals won't work. */
LPC_SYSCON->SYSAHBCLKCTRL |= ( (0x1 << 7) | (0x1 << 18) );
#if (CLOCK_SETUP) /* Clock Setup */
#if ((SYSPLLCLKSEL_Val & 0x03) == 1)
LPC_IOCON->PIO0_8 &= ~(0x3 << 3);
LPC_IOCON->PIO0_9 &= ~(0x3 << 3);
LPC_SWM->PINENABLE0 &= ~(0x3 << 4);
LPC_SYSCON->PDRUNCFG &= ~(0x1 << 5); /* Power-up System Osc */
LPC_SYSCON->SYSOSCCTRL = SYSOSCCTRL_Val;
__delayticks(1024); // cpldcpu 2013/06/23 replaced inefficient delay loop
#endif
#if ((SYSPLLCLKSEL_Val & 0x03) == 3)
LPC_IOCON->PIO0_1 &= ~(0x3 << 3);
LPC_SWM->PINENABLE0 &= ~(0x1 << 7);
__delayticks(1024); // cpldcpu 2013/06/23 replaced inefficient delay loop
#endif
LPC_SYSCON->SYSPLLCLKSEL = SYSPLLCLKSEL_Val; /* Select PLL Input */
LPC_SYSCON->SYSPLLCLKUEN = 0x01; /* Update Clock Source */
while (!(LPC_SYSCON->SYSPLLCLKUEN & 0x01)); /* Wait Until Updated */
#if ((MAINCLKSEL_Val & 0x03) == 3) /* Main Clock is PLL Out */
LPC_SYSCON->SYSPLLCTRL = SYSPLLCTRL_Val;
LPC_SYSCON->PDRUNCFG &= ~(0x1 << 7); /* Power-up SYSPLL */
while (!(LPC_SYSCON->SYSPLLSTAT & 0x01)); /* Wait Until PLL Locked */
#endif
#if (((MAINCLKSEL_Val & 0x03) == 2) )
LPC_SYSCON->WDTOSCCTRL = WDTOSCCTRL_Val;
LPC_SYSCON->PDRUNCFG &= ~(0x1 << 6); /* Power-up WDT Clock */
__delayticks(1024); // cpldcpu 2013/06/23 replaced inefficient delay loop
#endif
LPC_SYSCON->MAINCLKSEL = MAINCLKSEL_Val; /* Select PLL Clock Output */
LPC_SYSCON->MAINCLKUEN = 0x01; /* Update MCLK Clock Source */
while (!(LPC_SYSCON->MAINCLKUEN & 0x01)); /* Wait Until Updated */
LPC_SYSCON->SYSAHBCLKDIV = SYSAHBCLKDIV_Val;
#if __SYSTEM_CLOCK <= 30000000
LPC_FLASHCTRL->FLASHCFG=0; /* Set flash waitstates to zero if core clock is <=20 Mhz. Default is 1 waitstate */
#endif
#endif
}