tinySA/os/hal/platforms/LPC8xx/hal_lld.c

/*
    ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
                 2011,2012,2013 Giovanni Di Sirio.

    This file is part of ChibiOS/RT.

    ChibiOS/RT is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.

    ChibiOS/RT is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

/**
 * @file    LPC8xx/hal_lld.c
 * @brief   LPC8xx HAL subsystem low level driver source.
 *
 * @addtogroup HAL
 * @{
 */

#include "ch.h"
#include "hal.h"

/*===========================================================================*/
/* Driver exported variables.                                                */
/*===========================================================================*/

/*===========================================================================*/
/* Driver local variables.                                                   */
/*===========================================================================*/

/*===========================================================================*/
/* Driver local functions.                                                   */
/*===========================================================================*/

/*===========================================================================*/
/* Driver interrupt handlers.                                                */
/*===========================================================================*/

/*===========================================================================*/
/* Driver exported functions.                                                */
/*===========================================================================*/

/**
 * @brief   Low level HAL driver initialization.
 *
 * @notapi
 */
void hal_lld_init(void) {

  /* SysTick initialization using the system clock.*/
  nvicSetSystemHandlerPriority(HANDLER_SYSTICK, CORTEX_PRIORITY_SYSTICK);
  SysTick->LOAD = LPC8xx_SYSCLK / CH_FREQUENCY - 1;
  SysTick->VAL = 0;
  SysTick->CTRL = SysTick_CTRL_CLKSOURCE_Msk |
                  SysTick_CTRL_ENABLE_Msk |
                  SysTick_CTRL_TICKINT_Msk;
}

/**
 * @brief   LPC8xx clocks and PLL initialization.
 * @note    This function must be invoked only after the system reset.
 *
 * @special
 */
void lpc8xx_clock_init(void) {
  int i;

  /* Enable clocks to IOCON & SWM. */
  LPC_SYSCON->SYSAHBCLKCTRL |= ((1<<18)|(1<<7));

  /* System oscillator initialization.*/
#if (LPC8xx_PLLCLK_SOURCE == SYSPLLCLKSEL_SYSOSC)
  // switch off pull-ups
  LPC_IOCON->PIO0_8   &= ~(3<<3);
  LPC_IOCON->PIO0_9   &= ~(3<<3);
  
  // enable xtalin/xtalout
  LPC_SWM->PINENABLE0 &= ~(3<<4);

  LPC_SYSCON->SYSOSCCTRL = LPC8xx_SYSOSCCTRL;
  LPC_SYSCON->PDRUNCFG &= ~(1<<5);              /* System oscillator ON.    */
  for (i = 0; i<200; i++)
    __NOP();                                    /* Stabilization delay.     */
#endif

  /* CLKIN initialization.*/
#if (LPC8xx_PLLCLK_SOURCE == SYSPLLCLKSEL_CLKIN)
  // switch off pull-up
  LPC_IOCON->PIO0_1   &= ~(3<<3);

  // enable clkin
  LPC_SWM->PINENABLE0 &= ~(1<<7);
#endif

  /* Always set PLL clock source - 
     PLL IN can be a main clock source */
  LPC_SYSCON->SYSPLLCLKSEL = LPC8xx_PLLCLK_SOURCE;
  LPC_SYSCON->SYSPLLCLKUEN = 1;
  while (!(LPC_SYSCON->SYSPLLCLKUEN & 0x01));     /* Wait Until Updated       */

  /* PLL initialization.*/
#if LPC8xx_MAINCLK_SOURCE == SYSMAINCLKSEL_PLLOUT
  LPC_SYSCON->SYSPLLCTRL = LPC8xx_SYSPLLCTRL_MSEL | LPC8xx_SYSPLLCTRL_PSEL;
  LPC_SYSCON->PDRUNCFG &= ~(1<<7);            /* System PLL ON.           */
  while (!(LPC_SYSCON->SYSPLLSTAT & 1))      /* Wait PLL lock.           */
    ;
#endif

#if LPC8xx_MAINCLK_SOURCE == SYSMAINCLKSEL_WDGOSC
#error "WatchDog Oscillator not configured! Dont use as main clock source"
  LPC_SYSCON->WDTOSCCTRL = ??;
  LPC_SYSCON->PDRUNCFG  &= ~(1<<6);        /* WDT OSC On       */
  for (i = 0; i<200; i++)
    __NOP();                                    /* Stabilization delay.     */
#endif

  /* Flash wait states setting, the code takes care to not touch TBD bits.*/
  LPC_FLASHCTRL->FLASHCFG = (LPC_FLASHCTRL->FLASHCFG & ~1) |
                              LPC8xx_FLASHCFG_FLASHTIM;

  /* ABH divider initialization. Set this **before** switching Main clock
     source to ensure AHB clock stays in spec */
  LPC_SYSCON->SYSAHBCLKDIV = LPC8xx_SYSABHCLK_DIV;
  

  /* Main clock source selection.*/
  LPC_SYSCON->MAINCLKSEL = LPC8xx_MAINCLK_SOURCE;
  LPC_SYSCON->MAINCLKUEN = 1;
  while (!(LPC_SYSCON->MAINCLKUEN & 1));     /* Wait switch completion.  */

  /* Disable clocks to IOCON, SWM, FLASHREG & ROM. */
  LPC_SYSCON->SYSAHBCLKCTRL &= ~((1<<18)|(1<<7)|(1<<3)|(1<<1));

}

/** @} */