<tpb>
Title: Imgur: The magic of the Internet (at imgur.com)
<daveshah>
Very nice!
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<somlo>
daveshah: there's some "hidden slack" in nextpnr's timing analysis, it's usually rated at 52MHz tops, but feels pretty solid at 65MHz
<daveshah>
Yes, that's because it's based on Diamond's default model
<somlo>
some of the lingering weirdness includes passing memtest on svf push via openocd, but failing upon hitting the reset switch
<somlo>
pushing via openocd gets it to pass again (same bitstream)
<daveshah>
Which itself is worst process, minimum Vcc, 85 degrees C
<somlo>
but the latter is related to litedram, not timing, afaict, for the record...
<daveshah>
Have you tried another board yet? It does seem like something is marginal
<somlo>
not yet, will try that tomorrow
<daveshah>
I seem to remember a minimum frequency for the ECP5 DDRDLL
<daveshah>
that was around the 70MHz ish mark
<daveshah>
This was in my experiments before litedram
<daveshah>
It is possible something misbehaves in a way that varies between boards and chips below this
<daveshah>
Unfortunately I don't think it's actually documented anywhere
<somlo>
so maybe the versa has more slack than the trellisboard, since the former works OK at 55MHz (with rocket, that is), and the latter pretty consistently at 65, both of which are lower than the "official" number you quoted :)
<daveshah>
But a DDRDLL issue would explain why either it works or doesn't after a reset
<daveshah>
A typical "marginal" issue would likely not change after a reset and just be odd errors here or there, including in Linux
<somlo>
ok, so I'll add "unboxing a secontr trellisboard" to my agenda for tomorrow, then maybe adding sdcard support, so I can boot fedora or debian from there similarly to how LowRISC does it
<somlo>
as an alternative to a diskless NFS setup, which might be painful for other reasons... :)
<mithro>
somlo / daveshah: antmicro + kgugala are working on LiteSDCard support for both Linux and testing on hardware
<mithro>
Does the trellisboard have a sd card connector?
<daveshah>
Yes, it does
<mithro>
daveshah: What would we need to do to get antmicro a trellis board?
<daveshah>
I can't really encourage anyone to build more given there is an unknown DDR3 reliability issue
<daveshah>
Along with a few other rev 1.0 niggles
<daveshah>
I don't know if forksand or somlo would be able to part with one of theirs
<mithro>
daveshah: How similar is the versa board?
<daveshah>
mithro: smaller fpga, less ddr, no HDMI, only x1 pcie, less IO
<daveshah>
somlo: FYI, this patch was to get nfs boot working on a previous litex lnux project