(转)Cortex-M3 (NXP LPC1788)之SDRAM操作

网上看到了一些关于1788   SDRAM的调试代码，基本上都一样，本人在调试1788 SDRAM过程中，遇到了一些大麻烦，本人使用的的SDRAM芯片为MT48LC16M162.   本人遇到的问题如下：

1：   1788芯片硬件仿真初期，调试SDRAM寄存器配置错误，导致1788芯片无法进入仿真状态，只能用Flash Magic才能擦除。

2：  1788芯片的SDRAM有一个很重要的寄存器，官方驱动为   LPC_SC->EMCDLYCTL 寄存器的设置，就算你和官方所使用芯片一样，只要电路板有差异，这个寄存器的设置将有可能导致SDRAM在使用过程中出现错误。

3：  还有对于时序的设置，这一步相对来说就比较简单了。

 

下面例举出我的示例代码：

说明:

1：   至于端口配置本人参考官方NXP网站，如果你的端口有充足情况下面，本人建议你不要修改。

2：   本人的CPU主频为108M,不是120M，因为我的电路板的原因，在120M的时候，偶尔会有无法启动SDRAM的情况，所以为了安全本人使用了108M的主频。

 

 

#define SDRAM_REFRESH         7513
#define SDRAM_TRP             24
#define SDRAM_TRAS            40
#define SDRAM_TAPR            2
#define SDRAM_TDAL            2
#define SDRAM_TWR             18
#define SDRAM_TRC             70
#define SDRAM_TRFC            70
#define SDRAM_TXSR            78
#define SDRAM_TRRD            18
#define SDRAM_TMRD            2

 

void EMC_Init(void)  16 {  17  uint8_t i;  18 

 CLKPWR_ConfigPPWR(CLKPWR_PCONP_PCEMC, ENABLE);  21  LPC_SC->EMCDLYCTL   = (0x10 << 8) | (0 << 16) | (0 << 24) | 4;  22 
 LPC_EMC->Control  = 0x00000001;  24   LPC_EMC->Config   = 0x00000000;  25 

  PINSEL_ConfigPin(2,14,1);  28  PINSEL_ConfigPin(2,15,1);  29  PINSEL_ConfigPin(2,16,1);  30  PINSEL_ConfigPin(2,17,1);  31  PINSEL_ConfigPin(2,18,1);  32  PINSEL_ConfigPin(2,19,1);  33  PINSEL_ConfigPin(2,20,1);  34  PINSEL_ConfigPin(2,21,1);  35  PINSEL_ConfigPin(2,22,1);  36  PINSEL_ConfigPin(2,23,1);  37  PINSEL_ConfigPin(2,24,1);  38  PINSEL_ConfigPin(2,25,1);  39  PINSEL_ConfigPin(2,26,1);  40  PINSEL_ConfigPin(2,27,1);  41  PINSEL_ConfigPin(2,28,1);  42  PINSEL_ConfigPin(2,29,1);  43  PINSEL_ConfigPin(2,30,1);  44  PINSEL_ConfigPin(2,31,1);  45 
 for(i = 0; i < 32; i++)  47  {  48   PINSEL_ConfigPin(3,i,1);  49   PINSEL_ConfigPin(4,i,1);  50  }  51 
}  53 
 

int Sdram_Debug(void)  57 {  58  INT32U i=0,j,k;  59  volatile INT32U   *pmp;  60 

 pmp = (volatile INT32U *)BASE_SDRAMADDR;  63  j = SDRAM_SIZE/sizeof(*pmp);  64  for(i=0;i<j;i++)  65   pmp[i] = i;  66 
 for (k =0; k  < 1; k++)  68  {  69   for(i=0;i<j;i++)  70  {  71    if(pmp[i] != i)  72  {  73        while(1);  74       return FALSE;  75  }  76  }  77  }  78  return TRUE;  79 }  80 
 

#define P2C(Period)           (((Period<SDRAM_PERIOD)?0:(uint32_t)((float)Period/SDRAM_PERIOD))+1)

void SDRAMInit(void)  86 {  87  uint32_t i;  88  int dwtemp;  89  uint32_t uClk;  90  float SDRAM_PERIOD;  91  LPC_EMC->DynamicConfig0    = 0x00000680;  92  
 uClk = CLKPWR_GetCLK(CLKPWR_CLKTYPE_EMC);  94  uClk /= 1000000UL;  95  SDRAM_PERIOD = (float)1000/uClk;  96 
 LPC_EMC->DynamicRP = P2C(SDRAM_TRP);  98  LPC_EMC->DynamicRAS = P2C(SDRAM_TRAS);  99  LPC_EMC->DynamicSREX = P2C(SDRAM_TXSR); 100  LPC_EMC->DynamicAPR = SDRAM_TAPR; 101  LPC_EMC->DynamicDAL = SDRAM_TDAL+P2C(SDRAM_TRP); 102  LPC_EMC->DynamicWR = P2C(SDRAM_TWR); 103  LPC_EMC->DynamicRC = P2C(SDRAM_TRC); 104  LPC_EMC->DynamicRFC = P2C(SDRAM_TRFC); 105  LPC_EMC->DynamicXSR = P2C(SDRAM_TXSR); 106  LPC_EMC->DynamicRRD = P2C(SDRAM_TRRD); 107  LPC_EMC->DynamicMRD        = SDRAM_TMRD; 108  
 LPC_EMC->DynamicConfig0    = 0x00000680; 110  LPC_EMC->DynamicRasCas0    = 0x00000303; 111  LPC_EMC->DynamicReadConfig = 0x00000001; 112 
 TIM_Waitms(100); 114  LPC_EMC->DynamicControl    = 0x00000183; /* Issue NOP command */

 TIM_Waitms(200); 117  LPC_EMC->DynamicControl    = 0x00000103; 118  LPC_EMC->DynamicRefresh    = 0x00000002; 119 
 for(i = 0; i < 0x100; i++); 121 
LPC_EMC->DynamicRefresh    = P2C(SDRAM_REFRESH)>>4; 123 
 LPC_EMC->DynamicControl    = 0x00000083; /* Issue MODE command */

    dwtemp               = *((volatile int *)(SDRAM_BASE_ADDR | (0x33<<12))); 127  
 LPC_EMC->DynamicControl    = 0x00000000; 129 
 LPC_EMC->DynamicConfig0    = 0x00080680; 131  for(i = 0; i < 20000; i++); 132  Sdram_Debug(); 133 }

 

上面的LPC_SC->EMCDLYCTL 是我自己调试出来的准确的值，所以固定了。当然Segger公司有一个更好的办法计算LPC_SC->EMCDLYCTL，以下为参考Segger公司的函数。

 

static int _TestSDRAM(void) {  2   volatile uint32_t * pWriteLong;  3   volatile uint16_t * pWriteShort;  4  uint32_t Data;  5  uint32_t i;  6  uint32_t j;  7 
  pWriteLong  = (uint32_t*)SDRAM_BASE_ADDR;  9   pWriteShort = (uint16_t*)SDRAM_BASE_ADDR;  10   //
  // Fill 16 bit wise  12   //  13   for (i = 0; i < (SDRAM_SIZE / 0x40000); i++) {  14     for (j = 0; j < 0x100; j++) {  15       *pWriteShort++ = (i + j);  16       *pWriteShort++ = (i + j) + 1;  17  }  18  }  19   //
  // Verifying  21   //  22   pWriteLong = (uint32_t*)SDRAM_BASE_ADDR;  23   for (i = 0; i < (SDRAM_SIZE / 0x40000); i++) {  24     for (j = 0; j < 0x100; j++) {  25       Data = *pWriteLong++;  26       if (Data != (((((i + j) + 1) & 0xFFFF) << 16) | ((i + j) & 0xFFFF))) {  27         return 1;  // Error
 }  29  }  30  }  31   return 0;  // O.K.
}  33 
static void _FindDelay(int DelayType) {  35  uint32_t Delay;  36  uint32_t Min;  37  uint32_t Max;  38  uint32_t v;  39   Delay = 0x00;  40   Min   = 0xFF;  41   Max   = 0xFF;  42   //
  // Test for DLY min./max. values  44   //  45   while (Delay < 32) {  46     //
    // Setup new DLY value to test  48     //  49     if (DelayType == 0) {  50       v                 = LPC_SC->EMCDLYCTL & ~0x001Ful;  51       LPC_SC->EMCDLYCTL = v | Delay;  52     } else {  53       v                 = LPC_SC->EMCDLYCTL & ~0x1F00ul;  54       LPC_SC->EMCDLYCTL = v | (Delay << 8);  55  }  56     //
    // Test configured DLY value and find out min./max. values that will work  58     //  59     if (_TestSDRAM() == 0) {  60       //
      // Test passed, remember min. DLY value if not done yet  62       //  63       if (Min == 0xFF) {  64         Min = Delay;  65  }  66     } else {  67       //
      // Test failed, if a min. value has been found before, remember the current value for max.  69       //  70       if (Min != 0xFF) {  71         Max = Delay;  72  }  73  }  74     Delay++;  75  }  76   //
  // Calc DLY value  78   //  79   if        (Max != 0xFF) {  // If we found a min. and max. value we use the average of the min. and max. values to get an optimal DQSIN delay
    Delay = (Min + Max) / 2;  81   } else if (Min != 0xFF) {  // If we found only a min. value we use the average of the min. value and the longest DLY value to get an optimal DQSIN delay
    Delay = (Min + 0x1F) / 2;  83   } else {                   // No working max. and/or min. values found
    while (1);  // Fatal error
 }  86   //
  // Setup DLY value to work with  88   //  89   if (DelayType == 0) {  90     v                 = LPC_SC->EMCDLYCTL & ~0x001Ful;  91     LPC_SC->EMCDLYCTL = v | Delay;  92   } else {  93     v                 = LPC_SC->EMCDLYCTL & ~0x1F00ul;  94     LPC_SC->EMCDLYCTL = v | (Delay << 8);  95  }  96 }  97 

static uint32_t _CalibrateOsc(void) { 100  uint32_t Cnt; 101  uint32_t v; 102  uint32_t i; 103 
  //
  // Init start values 106   // 107   Cnt = 0; 108   //
  // Calibrate osc. 110   // 111   for (i = 0; i < 10; i++) { 112     LPC_SC->EMCCAL = (1 << 14);     // Start calibration
    v = LPC_SC->EMCCAL; 114     while ((v & (1 << 15)) == 0) {  // Wait for calibration done
      v = LPC_SC->EMCCAL; 116  } 117     Cnt += (v & 0xFF); 118  } 119   return (Cnt / 10); 120 } 121 
static void _AdjustEMCTiming(uint32_t Delay) { 123  uint32_t v; 124  uint32_t CmdDly; 125  uint32_t FBDelay; 126  uint32_t FBClkDly; 127 
  FBDelay = _CalibrateOsc(); 129 
  v = LPC_SC->EMCDLYCTL; 131   CmdDly            = ((v &  0x001Ful) * Delay / FBDelay) & 0x1F; 132   FBClkDly          = ((v &  0x1F00ul) * Delay / FBDelay) & 0x1F00; 133   LPC_SC->EMCDLYCTL =  (v & ~0x1F1Ful) | FBClkDly | CmdDly; 134 } 135 

void SDRAMInit(void) 138 { 139 uint32_t i; 140 int dwtemp; 141 uint32_t uClk; 142 float SDRAM_PERIOD; 143 LPC_EMC->DynamicConfig0 = 0x00000680; 144 
uClk = CLKPWR_GetCLK(CLKPWR_CLKTYPE_EMC); 146 uClk /= 1000000UL; 147 SDRAM_PERIOD = (float)1000/uClk; 148 LPC_EMC->DynamicRP = P2C(SDRAM_TRP); 149 LPC_EMC->DynamicRAS = P2C(SDRAM_TRAS); 150 LPC_EMC->DynamicSREX = P2C(SDRAM_TXSR); 151 LPC_EMC->DynamicAPR = SDRAM_TAPR; 152 LPC_EMC->DynamicDAL = SDRAM_TDAL+P2C(SDRAM_TRP); 153 LPC_EMC->DynamicWR = P2C(SDRAM_TWR); 154 LPC_EMC->DynamicRC = P2C(SDRAM_TRC); 155 LPC_EMC->DynamicRFC = P2C(SDRAM_TRFC); 156 LPC_EMC->DynamicXSR = P2C(SDRAM_TXSR); 157 LPC_EMC->DynamicRRD = P2C(SDRAM_TRRD); 158 LPC_EMC->DynamicMRD = SDRAM_TMRD; 159 
LPC_EMC->DynamicConfig0 = 0x00000680; 161 LPC_EMC->DynamicRasCas0 = 0x00000303; 162 LPC_EMC->DynamicReadConfig = 0x00000001; 163 
TIM_Waitms(100); 165 LPC_EMC->DynamicControl = 0x00000183; /* Issue NOP command */

TIM_Waitms(200); 168 LPC_EMC->DynamicControl = 0x00000103; 169 LPC_EMC->DynamicRefresh = 0x00000002; 170 
for(i = 0; i < 0x100; i++); 172 
LPC_EMC->DynamicRefresh = P2C(SDRAM_REFRESH)>>4; 174 
LPC_EMC->DynamicControl = 0x00000083; /* Issue MODE command */

dwtemp = *((volatile int *)(SDRAM_BASE_ADDR | (0x33<<12))); 178 
LPC_EMC->DynamicControl = 0x00000000; 180 
LPC_EMC->DynamicConfig0 = 0x00080680; 182  i = _CalibrateOsc(); 183  _FindDelay(0);  // EMCDLY
 _FindDelay(1);  // FBCLKDLY

 _AdjustEMCTiming(i); 187 }

 

本人因为SDRAM的问题，折腾了进半个月的时间，移植UCOSIII，YAFFS2，UCGUI , LWIP中间，程序本来是没有问题，因为SDRAM的问题，曾经好几次让我想放弃这个芯片，翻过了不知道多少遍M3的手册，看了不知道多少遍数据手册，不过最后我还是很幸运的调试出来....如果你现在的问题也出在SDRAM上面，那么希望本篇文章能给你些帮助。