AT91SAM9G45 DDR2 clock problem

Discussion around AT91RM9200 and SAM9 Series Products.

Moderator: nferre

Vanamak
Posts: 1
Joined: Fri Aug 03, 2018 4:11 am

AT91SAM9G45 DDR2 clock problem

Fri Aug 03, 2018 4:39 am

Hello,

We have a custom board based on at91sam9m10g45eknf dev board and we used to program it with bootstrap from at91sam9m10g45eknf eval board. But now, we have to change master clock to another value (100 MHz).
I have downloaded latest at91bootstrap from git repository, config it for at91sam9m10g45eknf and change pll and mck diveders value. But then i test new bootstrap I have an issue - mtest (running from u-boot) passes more slowly (looks like 4 times) than original bootloader. DDR clock is correct value - we've check it with oscilloscope. There is no errors on a mtest run. We tried run linux on the board - it goes correct, but loads slowly (noticeably).

As an additional test, I build a new at91bootstrap with same master clock as eval board bootloader - 133 MHz. And same issue again - Oscilloscope shows 133 MHz ddr clock but all stuff works slowly than original.

Bad thing - we don't have source files for original bootloader.

What could be the reason for such a slowdown?

Sorry for poor English.
Thank you,
Ivan.
blue_z
Location: USA
Posts: 1745
Joined: Thu Apr 19, 2007 10:15 pm

Re: AT91SAM9G45 DDR2 clock problem

Fri Aug 03, 2018 10:45 pm

Vanamak wrote:As an additional test, I build a new at91bootstrap with same master clock as eval board bootloader - 133 MHz.

Bad thing - we don't have source files for original bootloader.

What could be the reason for such a slowdown?
Obviously the slowdown is not caused by just a different master clock value, but rather a now-unknown configuration expected for your board.
Rather than try to guess the reason, you can simply use brute force (which could probably be more expedient anyway).
Assuming that you can boot U-Boot with both original and new versions of AT91Bootstrap, dump all of the registers of the PMC and both DRAM controllers.
Then account for all differences between the two configurations.

Regards

Return to “SAM9 ARM9 MPU”

Who is online

Users browsing this forum: No registered users and 1 guest