Hi,

I'm encountering this weird problem with writing to RAM on our custom board. Everytime I write to memory, it writes to two locations. One at the location that I want to write, and one other at address (Addr+0x400) or (Addr-0x400) (ex: writing to 0x31000000 would write the data to 0x31000000 and 0x31000400). Has anyone seen this issue before? Any suggestions on where I should look? Seems like it may be a configuration issue with the hardware but I'm not sure where to look.

To be specific, I use "mdb" command in Openocd Jtag Debugger for writing one byte. The CPU is Samsung S3C2440.

Any help is appreciated.

Thanks,
rp0777

Did you check if the RAM module is working 100% ? Did you try to write more and different adresses?
Are you sure if your code is doing only once? Not much else i can think right now.

Regards

Thanks for your reply.

The issue occurs on all 4 of our custom boards. So I'd assume the RAM modules are working good.

I did try writing, 1k of data, to multiple places (0x31000000, 0x31000800, 0x33f80000, 0x33f80f00, etc.) and got the same result.

I did check the code to make sure it's writing only once. Not only it occurs with OpenOCD, the issue also occurs when writing to ram using U-Boot.

In addition, I just found out a different behavior. When running the board without initializations from U-Boot and writing one byte to location ADDR_X (ex: 0x31000000), it writes to all 4 bytes from ADDR_X to ADDR_X+4. In this case, it doesn't write to ADDR_X+0x400 as in the previous case.

Thanks.

fyi, I found the solution to my problem. Not sure if it'll help anyone but I'm posting it here anyway. The problem's related to the SDRAM initialization for SCAN value. I changed the SCAN value to 8-bit column address number and it worked.

Thanks again for your help Ukiuki.