参考文档：
https://zhuanlan.zhihu.com/p/657819569
https://blog.csdn.net/weixin_41613969/article/details/126822480
https://blog.csdn.net/m0_69169562/article/details/143217380
https://blog.csdn.net/qq_42039294/article/details/112221396
https://blog.csdn.net/qq_45467083/article/details/109425825
https://blog.51cto.com/u_15262460/3243123
https://blog.51cto.com/u_15830484/5761618
https://blog.csdn.net/Simon223/article/details/107819310
https://blog.csdn.net/Ningjianwen/article/details/90940570
https://blog.csdn.net/chen18221987993/article/details/128970443
https://www.bilibili.com/video/BV13a411c7UK/?vd_source=2a185775b9481ebf3be36db7d3ece99a
一、配置STM32CUBEMX
配置信息安装芯片要求配置，这里使用的是W9825G6KH-6，配置在SDRAM1，起始地址为0xC0000000。
按照下列配置，配置相关数据：
二、初始化函数
sdram_fmc.h :
#ifndef __SDRAM_FMC_H__ #define __SDRAM_FMC_H__ #include "main.h" #define EXT_SDRAM_ADDR ((uint32_t)0xC0000000) // BANK1 0XC000 0000 BANK2 0XD000 0000 #define EXT_SDRAM_SIZE (32 * 1024 * 1024) // 内存大小 32MB = 256Mbit #define SDRAM_TEST_SIZE (4 * 16 * 1024) // 单次读写间隔 #define SDRAM_MODEREG_BURST_LENGTH_1 ((uint16_t)0x0000) #define SDRAM_MODEREG_BURST_LENGTH_2 ((uint16_t)0x0001) #define SDRAM_MODEREG_BURST_LENGTH_4 ((uint16_t)0x0002) #define SDRAM_MODEREG_BURST_LENGTH_8 ((uint16_t)0x0004) #define SDRAM_MODEREG_BURST_TYPE_SEQUENTIAL ((uint16_t)0x0000) #define SDRAM_MODEREG_BURST_TYPE_INTERLEAVED ((uint16_t)0x0008) #define SDRAM_MODEREG_CAS_LATENCY_2 ((uint16_t)0x0020) #define SDRAM_MODEREG_CAS_LATENCY_3 ((uint16_t)0x0030) #define SDRAM_MODEREG_OPERATING_MODE_STANDARD ((uint16_t)0x0000) #define SDRAM_MODEREG_WRITEBURST_MODE_PROGRAMMED ((uint16_t)0x0000) #define SDRAM_MODEREG_WRITEBURST_MODE_SINGLE ((uint16_t)0x0200) void SDRAM_Init(void); void fsmc_sdram_test(void); void sdram_test(void); #endifsdram_fmc.c :
#include "sdram_fmc.h" #include "fmc.h" #include "usart.h" static int SDRAM_SendCommand(uint32_t CommandMode, uint32_t Bank, uint32_t RefreshNum, uint32_t RegVal) { uint32_t CommandTarget; FMC_SDRAM_CommandTypeDef Command; if (Bank == 1) { CommandTarget = FMC_SDRAM_CMD_TARGET_BANK1; } else if (Bank == 2) { CommandTarget = FMC_SDRAM_CMD_TARGET_BANK2; } Command.CommandMode = CommandMode; Command.CommandTarget = CommandTarget; Command.AutoRefreshNumber = RefreshNum; Command.ModeRegisterDefinition = RegVal; if (HAL_SDRAM_SendCommand(&hsdram1, &Command, 0x1000) != HAL_OK) { return -1; } return 0; } void SDRAM_Init(void) { uint32_t temp; /* 1. 时钟使能命令 */ SDRAM_SendCommand(FMC_SDRAM_CMD_CLK_ENABLE, 1, 1, 0); /* 2. 延时，至少100us */ HAL_Delay(1); /* 3. SDRAM全部预充电命令 */ SDRAM_SendCommand(FMC_SDRAM_CMD_PALL, 1, 1, 0); /* 4. 自动刷新命令 */ SDRAM_SendCommand(FMC_SDRAM_CMD_AUTOREFRESH_MODE, 1, 8, 0); /* 5. 配置SDRAM模式寄存器 */ temp = (uint32_t)SDRAM_MODEREG_BURST_LENGTH_1 | //设置突发长度：1 SDRAM_MODEREG_BURST_TYPE_SEQUENTIAL | //设置突发类型：连续 SDRAM_MODEREG_CAS_LATENCY_3 | //设置CL值：3 SDRAM_MODEREG_OPERATING_MODE_STANDARD | //设置操作模式：标准 SDRAM_MODEREG_WRITEBURST_MODE_SINGLE; //设置突发写模式：单点访问 SDRAM_SendCommand(FMC_SDRAM_CMD_LOAD_MODE, 1, 1, temp); /* 6. 设置自刷新频率 */ /* SDRAM refresh period / Number of rows）*SDRAM时钟速度 – 20 = 64000(64 ms) / 2^13 *84MHz - 20 */ HAL_SDRAM_ProgramRefreshRate(&hsdram1, 636); } //uint16_t testsdram[250000] __attribute__((at(0XC0000000))); /* 测试用数组 */ //SDRAM内存测试 void fsmc_sdram_test(void) { __IO uint32_t i=0; __IO uint32_t temp=0; __IO uint32_t sval=0;//在地址0读到的数据 //每隔16K字节,写入一个数据,总共写入2048个数据,刚好是32M字节 for(i=0; i<EXT_SDRAM_SIZE; i+=SDRAM_TEST_SIZE) { HAL_SDRAM_Write_32b(&hsdram1, (uint32_t *)(EXT_SDRAM_ADDR+i), (uint32_t *)&temp, 1); // *(__IO uint32_t *)(EXT_SDRAM_ADDR+i) = temp; temp++; } printf("write over temp:%d \r\n", temp); //依次读出之前写入的数据,进行校验 for(i=0; i<EXT_SDRAM_SIZE; i+=SDRAM_TEST_SIZE) { HAL_SDRAM_Read_32b(&hsdram1, (uint32_t *)(EXT_SDRAM_ADDR+i), (uint32_t *)&temp, 1); printf("[%d] addr:%04x temp:%d \r\n",i/(SDRAM_TEST_SIZE) ,EXT_SDRAM_ADDR+i, temp); } }注：
绘制PCB，sdram的布线需要考虑等长和阻抗匹配，随便连接的导线可能导致数据传输错乱。
