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NeoGeo core: where is main .sdc file?
Posted: Mon Aug 24, 2020 3:57 pm
by sonycman
Hi!
Sorry for a silly question - but I just can't find .sdc file in NeoGeo core sources, where constraints for the SDRAM memory must be located.
There is sdram2.sdc file in /rtl/mem folder with constraints for the second SDRAM2 module, but thats it...
Am i missing something?
Re: NeoGeo core: where is main .sdc file?
Posted: Sat Aug 29, 2020 3:41 am
by Sorgelig
sdram2.sdc is leftover due to i didn't touch dualSDR config long time.
.sdc file is not required unless it's complex core and needs some relaxing in timings.
New SDRAM controller is written that way so no special constraints required.
Re: NeoGeo core: where is main .sdc file?
Posted: Sat Aug 29, 2020 3:12 pm
by sonycman
Oh, indeed?
And you are not having any issues with the memory stability between any builds?
Interesting. Thank you, Alexey.
Re: NeoGeo core: where is main .sdc file?
Posted: Mon Aug 31, 2020 9:25 am
by Sorgelig
No issues with official SDRAM module soldered carefully.
Even Archie using 126MHz has no issue with new SDRAM module. NeoGeo uses only 96MHz.
Re: NeoGeo core: where is main .sdc file?
Posted: Mon Aug 31, 2020 9:57 am
by sonycman
I`am planning to port NeoGeo core to Zynq Z-Turn board, thus I need to make my own SDRAM addon board.
Haven't you tried to place SDRAM chips on the different layers, one on top, and other on the bottom, one strictly over another?
This way would greatly reduce the length of the tracks.