LPC2478在启动代码里设置SDRAM，就不可以吗？
我有1个板子，硬件已经调试好，不用怀疑，用的Lpc2478主芯片，外挂2MB的SDRAM,options里勾上RAM1（ADDR=0xA0000000,SIZE=0x200000）,在启动代码不初始化，在系统启动后开始初始化SDRAM接口，可以测试SDRAM通过。但是把初始化内容放在启动代码里设置就不行，请教如何设置？#include <LPC24xx.H>
#define INT32U unsigned long
#define uint8_t unsigned char
// 硬件端口定义:
// BEEP: P0.0
#define BEEP (1<<0)
#define BeepOFF() FIO0SET |= BEEP
#define BeepON() FIO0CLR |= BEEP
void delay_Ns (int idly)
{
int i;
for(; idly > 0; idly--) {
for (i = 0; i < 5000; i++);
}
}
voidsysDelayNS(INT32UuiDly)
{
INT32Ui;
for(; uiDly > 0; uiDly--){
for(i = 0; i < 5000; i++);
}
}
voidSDRAMInit( void )
{
volatile INT32U i, dummy ;
LCD_CTRL = 0x00;
sysDelayNS(10);
PCONP |= 1 << 11;
/*
* 使能SDRAM总线连接
*/
#if 0
PINSEL4 |= 0x50000000;//SRAM(CS2,CS3)
PINSEL5 |= 0x05010555;//SDRAM(CS0,CS1)
PINSEL6 |= 0x55555555;//D0~D15
PINSEL8 |= 0x15555555;//A0~A15
PINSEL9 |= 0x50550000;//A16~A23 , /OE , /WE , BLS0 , BLS1 , /CS0 , /CS1;
EMC_CTRL = 0x00000001; /* Disable Address mirror */
#else
//原程序
PINSEL4 |= 0x50000000;//SRAM(CS2,CS3)
PINSEL5 |= 0x05050555;//SDRAM(CS0,CS1)
PINSEL6 |= 0x55555555;//D0~D15
PINSEL8 |= 0x55555555;//A0~A15
PINSEL9 |= 0x50555555;//A16~A23 , /OE , /WE , BLS0 , BLS1 , /CS0 , /CS1;
EMC_CTRL = 0x00000001; /* Disable Address mirror */
#endif
/*
* 设置SDRAM访问时序.
*/
EMC_DYN_RP = 1;
EMC_DYN_RAS = 2;
EMC_DYN_SREX = 1;
EMC_DYN_APR = 1;
EMC_DYN_DAL = 5;
EMC_DYN_WR = 2;
EMC_DYN_RC = 3;
EMC_DYN_RFC = 3;
EMC_DYN_XSR = 5;
EMC_DYN_RRD = 1;
EMC_DYN_MRD = 2;
EMC_DYN_RD_CFG = 1; /*Command delayed strategy */
/*
* Default setting,
* RAS latency 3 CCLKs,
* CAS latenty 3 CCLKs.
*/
EMC_DYN_RASCAS0 = 0x00000303;
/*
* 64MB, 1Mx16,
* 4 banks, row=12,
* column=8
*/
EMC_DYN_CFG0 = 0x00000280;
for (i = 0; i < 0x80; i++) {
}
/*
* Mem clock enable,
* CLKOUT runs, send command:
* NOP
*/
EMC_DYN_CTRL = 0x00000183;
for (i = 0; i < 0x80; i++) {
}
/*
* Send command:
* PRECHARGE-ALL,
* shortest possible refresh period
*/
EMC_DYN_CTRL = 0x00000103;
for (i = 0; i < 0x80; i++) {
}
/*
* set 32 CCLKs
* between SDRAM refresh
* cycles
*/
EMC_DYN_RFSH = 0x00000004;
for (i = 0; i < 0x80; i++) { /*wait 128 AHB clock cycles */
}
/*
* set 45 x 16CCLKs=720CCLK=15us
* between SDRAM refresh
* cycles
*/
EMC_DYN_RFSH = 45;
/*
* To set mode register in SDRAM,
* enter mode by issueMODE command, after finishing,
* bailout and back to NORMAL mode.
* Mem clock enable, CLKOUT runs, send command: MODE
*/
EMC_DYN_CTRL = 0x00000083;
dummy = *((volatile int *)(0xA0019800));
EMC_DYN_CTRL = 0x00000000; /*Send command: NORMAL */
EMC_DYN_CFG0 = 0x00080280; /*Enable buffer */
for (i = 0; i < 0x80; i++) {
}
}
#define TEST_ADDR 0xA011FF00 /* 测试起始地址 */
#define SIZE 100 /* 测试100个SDRAM空间 */
int main(void)
{
INT32U i;
uint8_t * p_uint8_t = (uint8_t *)TEST_ADDR;
PINSEL0= 0x00;
SCS |= 0x01;
FIO0DIR |= BEEP;
BeepON();
delay_Ns(100);
BeepOFF();
SDRAMInit(); // 启动代码里的设置和这里是一样的值。
// 测试SDRAM连接是否正常
p_uint8_t = (uint8_t *)TEST_ADDR;
for (i=0;i < SIZE;i++)
*p_uint8_t++ = (uint8_t)i;
p_uint8_t = (uint8_t *)TEST_ADDR;
for(i=0; i<SIZE; i++)
{
if( *p_uint8_t != (uint8_t)i )
{
while(1);
}
p_uint8_t++;
}
// end
while(1) {
BeepON();
delay_Ns(500);
BeepOFF();
delay_Ns(500);
}
} 在SDRAM中运行是需要2段独立代码的，不知道的初始化运行，又是开始运行的指的是那段代码？ 围观中，我来学习的 没仔细看楼主的程序，不过楼主可以看下，在你初始化C语言前，是不是已经建立好了RW段和ZI段，不然的话，没有搭建好C环境，只能用汇编来实现初始化
页:
[1]