• SDRAM是同步动态随机存储器，iCore4T ARM+FPGA双核心板挂有一片容量为32M的外部SDRAM，在前面项目的基础上，分享RTT的SDRAM驱动移植，最后实现外部SDRAM的读写测试。

http://www.gkwiki.cn/doku.php?id=icore4t_60

#ifndef __SDRAM_PORT_H
#define __SDRAM_PORT_H
#ifdef __cplusplus
 extern "C" {
#endif
 
#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) 
#define SDRAM_REFRESH_COUNT                     ((uint32_t)0x0603)
 
#define LOADTOACTIVEDELAY                        2
#define EXITSELFREFRESHDELAY                     7
#define SELFREFRESHTIME                          4
#define ROWCYCLEDELAY                            7
#define WRITERECOVERYTIME	                       2
#define RPDELAY                                  2
#define RCDDELAY                                 2
 
#define SDRAM_BANK_ADDR                          ((uint32_t)0xC0000000)
#define SDRAM_SIZE                               ((uint32_t)0x2000000)
#define SDRAM_DATA_WIDTH                         16
 
#define SDRAM_TARGET_BANK                        1
#define SDRAM_COLUMN_BITS                        9
#define SDRAM_ROW_BITS                           13
#define SDRAM_CAS_LATENCY                        3
#define SDCLOCK_PERIOD                           2
#define SDRAM_RPIPE_DELAY                        1
 
#ifdef __cplusplus
}
#endif
#endif /*__ SDRAM_PORT_H */

至此说明我们的外部SDRAM驱动已经添加成功。

源代码可以移步这里下载：

链接：https://pan.baidu.com/s/1fcLU4WaRDlgr0mNYwZj1Yg  提取码：zstq