Question about an error using external SRAM on MPC5777C-512DS EVB

[youngseolee]

I am trying to access the external SRAM in the MPC5777C-512DS EVB.

I implemented the test code by referring to the already posted example code(EBI Bus Clock: 33MHz),

and it was confirmed that Read/Write Access to the external SRAM is possible without any problem when the code is executed.

I increased the EBI bus clock to 66MHz and checked the write/read access to the external SRAM in the same way.
(I know that the external SRAM applied to the EVB is supported up to 166MHz)

When I set 'SIU_ECCR = 0x1001' and executed the program, I noticed the following error.

-> Even if data is written only to address 0x2000_0000, all values are written in 0x2000_0000 - 0x2000FFFF area.

The register setting values for clock setting are as follows.

- PLLDIG_PLL0DV: 0x60035048
- PLLDIG_PLL1DV: 0x00020016
- SIU_SYSDIV: 0x05002110

Am I missing something to increase the EBI Bus Clock to 66MHz?

What should I check to solve this problem?

[davidtosenovjan]

I am also been using 33MHz for EBI CLKOUT and I may confirm it does not work with 66MHz. I remember I have tried various configurations without success.

Unfortunately a reason is unknown to me. It would be necessary to analyze timing of used memory and MPC5777C's EBI specification. EVB may not be necessarily error-free.

However maximum clockout frequency is 66MHz, not 166MHz as you said.

[youngseolee]

Thanks for your reply.

The 166MHz clock I mentioned was the maximum operating frequency of the SRAM configured in the EVB, not the EBI clock.

If so, can this problem that does not work when EBI Clock is set to 66MHz is not an MPC5777C error but an MPC5777C-512DS EVB error?

[davidtosenovjan]

Yes, I think it could be so.