MPC8280 SDRAM 60x Bus配置问题

[lhb_will]

在外面集成了两块SDRAM，型号是MT48LC4M32B2-。但是按照如下命令进行写时发现0x8地址的写入会修改0、0x10、0x1C地址的数据。请问可能是哪里没配置好？

[alexander_yakov]

SDRAM memory chips require initialization sequence after power-on. Please look MPC8280 Reference Manual, Section 11.4.2 "SDRAM Power-On Initialization" for the exact sequence.

https://www.nxp.com/docs/en/reference-manual/MPC8280RM.pdf

[lhb_will]

如果我使用两块MT48LC4M32B2组成64bit数据，连接到60x BUS上的CS1片选上。B60x_ADD28连接到SDRAM的A0，B60x_ADD27连接到SDRAM的A1...B60x_ADD16连接到SDRAM的A12，其中SDA10连接到SDRAM的A10，BNKSEL连接到SDRAM的BA。PSDMR配置为0xc24b36a3，OR1配置为0xfe002ec0，BR1配置为0xf0000041，SIUMCR配置为0x0e200000。这样是否正确。下面是我的SDRAM初始化序列。

writemmr OR1 0xfe002ec0
writemmr BR1 0x00000041

writemmr PSRT 0x13

writemmr MPTPR 0x2800

# precharge all banks
writemmr PSDMR 0x824b36a3
writemmr PSDMR 0xaa4b36a3

# perform an access
writemem.b 0x00000000 0x00

# cbr refresh
writemmr PSDMR 0x8a4b36a3

# perform 8 accesses
writemem.b 0x00000000 0xFF
writemem.b 0x00000000 0xFF
writemem.b 0x00000000 0xFF
writemem.b 0x00000000 0xFF
writemem.b 0x00000000 0xFF
writemem.b 0x00000000 0xFF
writemem.b 0x00000000 0xFF
writemem.b 0x00000000 0xFF

; Issue Mode register write
writemmr PSDMR 0x9a4b36a3

writemem.b 0x00000190 0x00

writemmr PSDMR 0xc24b36a3

[lhb_will]

我看在AN2165中有个描述写的是在MPC8260A中“the MPC8260A (HiP4) and revision C of the MPC8260 can use these values but require an external multiplexer.”是否MPC8280CVVQLDA型号也是如此？

[alexander_yakov]

Yes