low_level_init.c

NXP ARM处理器240*320液晶驱动程序（IAR开发环境）

/***********************************************************************
 * File:   low_level_init.c
 * Rev:    1.0
 * Author: Chun Sing Chu
 * Date:   March 26 2007
 *
 * Description:
 *     This file contains low level initialization of the LPC2478.
 *
 * Revision History:
 * Rev 1.0 March 26 2007
 * Initial revision.
 * 
 **********************************************************************/

#include "irq.h"
#include "low_level_init.h"
#include "ex_sdram.h"

/***********************************************************************
 *
 * Function: delayMs
 *
 * Purpose: Start the timer delay in micro seconds until elapsed.
 *
 * Processing:
 *
 * Parameters: 	Delay value in micro second
 *
 * Outputs: None
 *
 * Returns: None
 *
 **********************************************************************/
void delayMs(INT32U delayInMs)
{
    T1TCR = 0x02; /* reset timer */
    T1PR  = 0x00; /* set prescaler to zero */
    T1MR0 = delayInMs * (18000000 / 1000); /* PCLK is 1/4 CCLK */ 

    T1IR  = 0xFF; /* reset all interrrupts */
    T1MCR = 0x04; /* stop timer on match */
    T1TCR = 0x01; /* start timer */
  
    /* wait until delay time has elapsed */
    while (T1TCR & 0x01);
}

/***********************************************************************
 *
 * Function: configure_pll
 *
 * Purpose: switching to main OSC from IRC.
 *
 * Processing:
 *
 * Parameters: 	None
 *
 * Outputs: None
 *
 * Returns: None
 *
 **********************************************************************/
void configure_pll(void)
{
    INT16U MValue, NValue;

    if (PLLSTAT_bit.PLLC)
    {
        PLLCON_bit.PLLC = 0x0; /* PLL disconnected */
        PLLFEED = 0xaa;
        PLLFEED = 0x55;
    }

    PLLCON_bit.PLLE = 0x0; /* PLL disabled */
    PLLFEED = 0xaa;
    PLLFEED = 0x55;
    
    SCS_bit.OSCEN = 0x1; /* Enable main OSC */
    while(!SCS_bit.OSCSTAT); /* Wait until main OSC is usable */

    CLKSRCSEL_bit.CLKSRC = 0x1;	/* select main OSC, 12MHz, as the PLL clock source */

    PLLCFG_bit.MSEL = PLL_MValue;
    PLLCFG_bit.NSEL = PLL_NValue;
    PLLFEED = 0xaa;
    PLLFEED = 0x55;
      
    PLLCON_bit.PLLE = 0x1; /* PLL enabled */
    PLLFEED = 0xaa;
    PLLFEED = 0x55;

    CCLKCFG_bit.CCLKSEL = CCLKDivValue;	/* Set clock divider */

    while (!PLLSTAT_bit.PLOCK);	/* Check lock bit status */
    
    MValue = PLLSTAT_bit.MSEL;
    NValue = PLLSTAT_bit.NSEL;
    while ((MValue != PLL_MValue) && (NValue != PLL_NValue));

    PLLCON_bit.PLLC = 0x1; /* PLL connected */
    PLLFEED = 0xaa;
    PLLFEED = 0x55;
    while (!PLLSTAT_bit.PLLC); /* Check connect bit status */
}

/***********************************************************************
 *
 * Function: low_level_init
 *
 * Purpose: initialize the chip.
 *
 * Processing:
 *
 * Parameters: 	None
 *
 * Outputs: None
 *
 * Returns: None
 *
 **********************************************************************/
void low_level_init(void)
{
    /* Configure PLL, switch from IRC to Main OSC */
    configure_pll();

    PCLKSEL0 = 0x00000000;	/* PCLK is 1/4 CCLK */
    PCLKSEL1 = 0x00000000;


    SDRAMInit();
    ClearMemory();
    PCONP |= 0x00100000;        /* Power Control for CLCDC */ 

    /* Set memory accelerater module*/
    MAMCR = 0;
    MAMTIM = 3; /* Fcclk > 40MHz */
//    MAMTIM = 2; /* Fcclk >= 20MHz */
//    MAMTIM = 1; /* Fcclk < 20MHz */
    MAMCR = 2;

    init_vic();
}