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litex-hub / litehyperbus

Small footprint and configurable HyperBus core
BSD 2-Clause "Simplified" License
10 stars 5 forks source link

Add CrossLink-NX support #2

Open daveshah1 opened 4 years ago

daveshah1 commented 4 years ago

The Lattice CrossLink-NX VIP board has two S27KS0641DPBHI020 HyperRAM chips on it; it would be nice to support them.

It looks like, by coincidence or purpose, one of the two chips is wired in such a way that DQS primitives could be used to get a legal 4:1 (or 8:1) bidirectional gearing.

Otherwise, for Radiant support, the PHY can only be 2:1 as, without using DQS, only the simple DDR primitives can be used on bidirectional pins (based on the bitdocs I have so far, it is similar to ECP5 so once nextpnr is up and running that would support bidirectional 4:1/8:1.)

gregdavill commented 4 years ago

Nice find, I did not realise they put HyperRAM on this board. That will be a good addition, I've been looking for some more targets to support.