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。
1 #define SDRAM_REFRESH 7513 2 #define SDRAM_TRP 24 3 #define SDRAM_TRAS 40 4 #define SDRAM_TAPR 2 5 #define SDRAM_TDAL 2 6 #define SDRAM_TWR 18 7 #define SDRAM_TRC 70 8 #define SDRAM_TRFC 70 9 #define SDRAM_TXSR 78 10 #define SDRAM_TRRD 18 11 #define SDRAM_TMRD 2 12 13 14 15 void EMC_Init(void) 16 { 17 uint8_t i; 18 19 20 CLKPWR_ConfigPPWR(CLKPWR_PCONP_PCEMC, ENABLE); 21 LPC_SC->EMCDLYCTL = (0x10 << 8) | (0 << 16) | (0 << 24) | 4; 22 23 LPC_EMC->Control = 0x00000001; 24 LPC_EMC->Config = 0x00000000; 25 26 27 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 46 for(i = 0; i < 32; i++) 47 { 48 PINSEL_ConfigPin(3,i,1); 49 PINSEL_ConfigPin(4,i,1); 50 } 51 52 } 53 54 55 56 int Sdram_Debug(void) 57 { 58 INT32U i=0,j,k; 59 volatile INT32U *pmp; 60 61 62 pmp = (volatile INT32U *)BASE_SDRAMADDR; 63 j = SDRAM_SIZE/sizeof(*pmp); 64 for(i=0;i DynamicConfig0 = 0x00000680; 92 93 uClk = CLKPWR_GetCLK(CLKPWR_CLKTYPE_EMC); 94 uClk /= 1000000UL; 95 SDRAM_PERIOD = (float)1000/uClk; 96 97 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; 108 109 LPC_EMC->DynamicConfig0 = 0x00000680; 110 LPC_EMC->DynamicRasCas0 = 0x00000303; 111 LPC_EMC->DynamicReadConfig = 0x00000001; 112 113 TIM_Waitms(100); 114 LPC_EMC->DynamicControl = 0x00000183; /* Issue NOP command */115 116 TIM_Waitms(200); 117 LPC_EMC->DynamicControl = 0x00000103;118 LPC_EMC->DynamicRefresh = 0x00000002; 119 120 for(i = 0; i < 0x100; i++); 121 122 LPC_EMC->DynamicRefresh = P2C(SDRAM_REFRESH)>>4; 123 124 LPC_EMC->DynamicControl = 0x00000083; /* Issue MODE command */125 126 dwtemp = *((volatile int *)(SDRAM_BASE_ADDR | (0x33<<12)));127 128 LPC_EMC->DynamicControl = 0x00000000; 129 130 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。
1 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 8 pWriteLong = (uint32_t*)SDRAM_BASE_ADDR; 9 pWriteShort = (uint16_t*)SDRAM_BASE_ADDR; 10 // 11 // 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 // 20 // 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 28 } 29 } 30 } 31 return 0; // O.K. 32 } 33 34 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 // 43 // Test for DLY min./max. values 44 // 45 while (Delay < 32) { 46 // 47 // 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 // 57 // Test configured DLY value and find out min./max. values that will work 58 // 59 if (_TestSDRAM() == 0) { 60 // 61 // Test passed, remember min. DLY value if not done yet 62 // 63 if (Min == 0xFF) { 64 Min = Delay; 65 } 66 } else { 67 // 68 // 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 // 77 // 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 80 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 82 Delay = (Min + 0x1F) / 2; 83 } else { // No working max. and/or min. values found 84 while (1); // Fatal error 85 } 86 // 87 // 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 98 99 static uint32_t _CalibrateOsc(void) {100 uint32_t Cnt;101 uint32_t v;102 uint32_t i;103 104 //105 // Init start values106 //107 Cnt = 0;108 //109 // Calibrate osc.110 //111 for (i = 0; i < 10; i++) {112 LPC_SC->EMCCAL = (1 << 14); // Start calibration113 v = LPC_SC->EMCCAL;114 while ((v & (1 << 15)) == 0) { // Wait for calibration done115 v = LPC_SC->EMCCAL;116 }117 Cnt += (v & 0xFF);118 }119 return (Cnt / 10);120 }121 122 static void _AdjustEMCTiming(uint32_t Delay) {123 uint32_t v;124 uint32_t CmdDly;125 uint32_t FBDelay;126 uint32_t FBClkDly;127 128 FBDelay = _CalibrateOsc();129 130 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 }135 136 137 void SDRAMInit(void)138 {139 uint32_t i;140 int dwtemp;141 uint32_t uClk;142 float SDRAM_PERIOD;143 LPC_EMC->DynamicConfig0 = 0x00000680;144 145 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; 159 160 LPC_EMC->DynamicConfig0 = 0x00000680; 161 LPC_EMC->DynamicRasCas0 = 0x00000303; 162 LPC_EMC->DynamicReadConfig = 0x00000001; 163 164 TIM_Waitms(100); 165 LPC_EMC->DynamicControl = 0x00000183; /* Issue NOP command */166 167 TIM_Waitms(200); 168 LPC_EMC->DynamicControl = 0x00000103;169 LPC_EMC->DynamicRefresh = 0x00000002; 170 171 for(i = 0; i < 0x100; i++); 172 173 LPC_EMC->DynamicRefresh = P2C(SDRAM_REFRESH)>>4; 174 175 LPC_EMC->DynamicControl = 0x00000083; /* Issue MODE command */176 177 dwtemp = *((volatile int *)(SDRAM_BASE_ADDR | (0x33<<12)));178 179 LPC_EMC->DynamicControl = 0x00000000; 180 181 LPC_EMC->DynamicConfig0 = 0x00080680; 182 i = _CalibrateOsc();183 _FindDelay(0); // EMCDLY184 _FindDelay(1); // FBCLKDLY185 186 _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。