<azonenberg>
actually, that was done just before i bought Sonnet so i've improved even further
<azonenberg>
The big parasitic to be concerned about with high value RF resistors is capacitive coupling across the terminals
<azonenberg>
there's about 26 fF between the terminals and with a 1K resistor you'd have significantly more signal going through the shunt cap than the resistance itself
<azonenberg>
5x 200R was my early attempt at balancing that
<azonenberg>
i later did some more complete s-parameter modeling and found that 2x 200R + 1x 50R, for a 10:1 probe instead of 21:1, is much flatter out to 10 GHz
<azonenberg>
But 5x 200 is still way better than 1x 1K
<azonenberg>
this is using vishay FC series specifically
<florolf>
ah, i see.
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<ZirconiumX>
Ugh, I hate it when synthesis is unnecessarily picky
<ZirconiumX>
So, I was building attosoc, and got a firmware.hex which was 150 words (at least Quartus said as much)
<ZirconiumX>
s/words/bytes/
<ZirconiumX>
But attosoc specifies 256 bytes in ROM_BYTES
<ZirconiumX>
So Quartus rejected firmware.hex and replaced the ROM file with all-zeroes
<ZirconiumX>
And then proceeded to turn an all-zero ROM into a constant driver
<ZirconiumX>
And then optimised the entire design away
<ZirconiumX>
s/ROM file/ROM init data/
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<tnt>
So ... who bought off all the UP5k from digikey ?
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<emeb>
Wasn't me. :)
<emeb>
plenty for UWG30 pkg available though.
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<emeb>
I've finally got some time to play with the ULX3S. I've got pjtrellis built & installed, as well as updated yosys and nextpnr-ecp5.
<emeb>
What's the best tool for downloading to the ULX3S? I see the ujprog tool is used in some examples, but it seems kind of dodgy.
<daveshah>
I think ujprog is recommended
<daveshah>
There is also some openocd support (not sure if upstream) and various ways of WiFi programming
<emeb>
OK, thanks.
<emeb>
The build process for ujprog is very broken - assumes paths for libraries, etc.
<TD-Linux>
I use ujprog with mine but yes it is not great
<TD-Linux>
I get the impression that wifi is supposed to be the primary way, but I haven't soldered the esp32 on mine yet
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<emeb>
OK, seem to have ujprog built (compiled w/o errors at least)
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<emeb>
but now when running it I get "ULX2S / ULX3S JTAG programmer v 3.0.92 (built Feb 13 2020 12:47:15)
<emeb>
Cannot find JTAG cable."
<emeb>
I can see a /dev/ttyUSB0 and running a terminal on it shows a bunch of status which I assume is from the factory image.
<emeb>
is there some special incantation needed to convince ujprog that there's actually something there?
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<emeb>
ah - FT231X is "factory default" & needs to be programmed with ULX3S mfg strings in order for ujprog to see it.
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<emeb>
and of course the ftx_prog binary is linked against lib versions I don't have
<TD-Linux>
emeb, are you using the right usb port?
<TD-Linux>
oh yeah you need to flash it
<emeb>
hacking away, trying to get ftx_prog to work...
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<emeb>
great - ftx_prog complaining about bad crc
<tnt>
Oh yeah, I remember that step failed for me.
<emeb>
any clues on a solution?
<emeb>
haha "--ignore-crc-error" option, but using it gives "ftdi_write_eeprom_location() failed: Invalid access to checksum protected area below 0x80"
<TD-Linux>
I don't remember what I did to fix it
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<TD-Linux>
oh
<TD-Linux>
I'm starting to remember. I think I used either a different version of the ftdi libraries, or a different binary
<emeb>
Seems it's not an issue for me - just did a --dump and the right strings are in there.
<emeb>
so for some reason my ujprog still doesn't work right
<TD-Linux>
my binary is linked against .1 so I must have not changed that
<emeb>
I rebuilt my from source
<TD-Linux>
I can mess with mine a bit when I get home. it's been a while since I've used it because I got distracted by other fpgas :^)
<emeb>
still failed
<emeb>
Is it just me or is the host-side programming support for ULX3S kinda... rickety?
<emeb>
all this reliance on borken FTDI stuff and shipping binaries around...
<TD-Linux>
yeah, I would have been happy with it just being ecp5 evn compatible
<TD-Linux>
technically it's still preproduction hardware though
<emeb>
sure acts like it. :)
<tnt>
It has a jtag port :p
<emeb>
so yeah - my FT231 has Product = ULX3S FPGA 12K v3.0.3
<emeb>
already in it
<emeb>
but the FPGA is an 85K - do you suppose that will make any difference?
<tnt>
No I meant ... you can use any _other_ jtag adapter :p
<tnt>
I used a glasgow until I managed to get the ft231 to behave (and sorry, can't remember what I did ... tried a bunch, something worked in the end, I just wiped it all from my memory after that)
<TD-Linux>
emeb, I think I edited mine to say 85K but I don't think it actually matters
<emeb>
cool - thx
<emeb>
tnt: haha - understood.
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<edbordin>
has anyone found or RE'd a schematic for the tang primer board yet? curious what the pinout is on the ribbon connectors, don't have the appropriate ribbon yet to map it out myself
<edbordin>
well... ffc. Idk if that is really what people call ribbon
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<emeb>
OK - digging deeper into the ujprog issue - seems that sometimes when the ULX3S is plugged into USB it doesn't enumerate w/ the custom MFG & Prod strings but uses the default FTDI ones.
<emeb>
So I added a cable path to ujprog that includes the default Prod string - this works.
<TD-Linux>
strange
<TD-Linux>
power sequencing issue?
<emeb>
no idea
<emeb>
Now it's time to figure out how to build the blinky example for 85k instead of 45k
<emeb>
not used to the way ecp5 stuff works - config files, etc.
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<emeb>
w00t - blinky works
<emeb>
damn but it takes a while to program.
<edbordin>
I hear compressed bitstreams are worth setting up to save time there
<emeb>
cool - something else to figure out!
<daveshah>
--compress argument to ecppack
<emeb>
thanks - that worked.
<emeb>
seems like it's about 3x faster or so
<daveshah>
If its a blinky I'd expect more like 7x
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<daveshah>
Possible there is something else slowing things down
<emeb>
Could just be my subjective time sense too. :P