topic Re: LPC54018 + SDRAM W9864G6KH has problem in LPC Microcontrollers

LPC54018 + SDRAM W9864G6KH has problem

junzhang8421 — Wed, 29 May 2019 09:21:01 GMT

On LPC54S018-EVK board, its schematics uses W9812G6JB SDRAM, but on actual board, it's IS42S16800 SDRAM. In source code it still uses W9812G6JB configuration. I want to know if W9812G6JB actually bring up on this board? or W9812G6JB has problem, so in later product board, SDRAM is changed to use ISSI chip?

Now I use W9864G6KH SDRAM on LPC54018 board, configuration using SDRAM_DEV_MEMORYMAP (0x05u) and try SDRAM_MODEREG_VALUE with (0x33u), (0x23), (0x233), but all has problem, it occur as below:

1. when I fill memory with memset(), all memory can be filled correctly.

2. when I use memcpy() to copy data from .data sector to SDRAM, Data in SDRAM always is wrong.

3. I use a loop-mode, to read ulong from .data sector and write to SDRAM. If I use step mode one by one via emulator, the data in SDRAM is also correct. But if I run directly, data in SDRAM still is wrong.

Please share your comments, thank you in advance!

Re: LPC54018 + SDRAM W9864G6KH has problem

junzhang8421 — Thu, 30 May 2019 05:04:26 GMT

Dear all

I found the root-cause now.

Maybe the internal SDRAM bus is conflict with external SDRAM bus. If true copying data from internal SDRAM to extenal SDRAM always cause bus error, so the memcpy() result is not correct as we expect.

If using memset() to fill extenal SDRAM, it only writes one register to SDRAM, which cannot cause bus conflict.

Today, I try to read data from SD card to external SDRAM, the data is also correct.

Now question is: do we have solution to copy data between internal SDRAM and external SDRAM correctly?

Re: LPC54018 + SDRAM W9864G6KH has problem

soledad — Thu, 20 Jun 2019 18:07:03 GMT

Hi,

please check the following thread:

https://community.nxp.com/thread/456814

I hope this helps, have a nice day

Regards

Soledad