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SDRAM data bytes shifting

Question asked by Muralidhar M on Oct 12, 2018

the scenario is

when we write and read immediate it is working fine ,if we read after some time the the data bytes are shifting 2-4 bytes but occur randomly

example

the data written to SD RAM

0xA0000000 -> 0x00000000  0x44332211    0x88776655

0xA000000C->0x000000001 0x44332211    0x88776655

....

.....

data reading after some time

0xA0000000 -> 0x00000000  0x44332211    0x88778877

0xA000000C->0x000000001 0x44332211    0x88776655

 

 

the SD RAM we used is     AS4C4M16SA-6TIN

 

the timming we have initialized

are

#define SDRAM_REFRESHPERIOD_NS (64 * 1000000 / 4096) /* 4096 rows/ 64ms */
#define SDRAM_TRP_NS (21u)
#define SDRAM_TRAS_NS (42u)
#define SDRAM_TSREX_NS (67u)
#define SDRAM_TAPR_NS (20u)
#define SDRAM_TWRDELT_NS (6u)
#define SDRAM_TRC_NS (60u)
#define SDRAM_RFC_NS (60u)
#define SDRAM_XSR_NS (67u)
#define SDRAM_RRD_NS (14u)
#define SDRAM_MRD_NCLK (2u)
#define SDRAM_RAS_NCLK (2u)
#define SDRAM_MODEREG_VALUE (0x33u)
#define SDRAM_DEV_MEMORYMAP (0x05u) /* 64Mbits (4M*16, 4banks, 12 rows, 8 columns)*/

 

we used SDK emc files .

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