I have a design on PPC405EP processor.
In my design, a 2M * 32 bit SDRAM is used. But in practice, Only One typ of SDRAM chip is supported, other Chip can not work in same configure.
I set the SDRAM config register as the following: #define SDRAM_CFG 0x80800000 #define SDRAM_RTR 0x08200000 /* Define 133M refreshing rate. 133MHz #define SDRAM_B0CR 0x00828001 /* 8M, Base=0x800000(8MB) */ #define SDRAM_B1CR 0x00028001 /* 8M, Base=0 , Mode 5 (11 * 8 * 4) */ #define SDRAM_TR 0x018FC01B
EM638325 which made by ETRON Co. is supported, The other chip can no work. Such as: K4S643232, W986432, 48LC2M32, VT3664324, and so on, the all have -6 ns feature, working properly at 133Mhz on other system. I hav check the data sheet of these chip, they are compatible and suitable fo the actural configure.
But after many times trying, the other chips can not work properly. The problem is like the following: First write Data1 to Address1, and then write Data2 to Address2, Third, Read from Address1 and Address2, the result is both Data2.
Because the EM638325 is difficult to purchase now, I need a replacer. Please help me.
Thanks and Regards.
Rivor Wang
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