[Libre-soc-dev] ulx3s-85k successful BIOS boot at 10mhz

[Luke Kenneth Casson Leighton]

hooray. i can confirm that a successful BIOS boot occurs at [only] 10 mhz
on the ULX3S-85k which just arrived today.  whilst this is horrendously
slow it is a starting point from which analysis of timing reports can be done
to find the excessively-long combinatorial loops and break them.

in parallel with that, the nice thing about the ulx3s-85k is that it uses
SDRAM1 which does not need "training" and unlike DDR3 ICs which
typically cannot run below around 48-55 mhz, SDRAM1 is quite happy
at 10mhz.  consequently if absolutely forced to i can try running
linux-5.7 at that speed.

l.

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crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68