13:55 <d1b2> <atx> https://lwn.net/Articles/820320/

13:55 <d1b2> <atx> Interesting

13:56 <d1b2> <atx> This could be used to provide an actual /dev/i2c thing by glasgow

13:56 <d1b2> <atx> Does not look merged yet

15:05 <lukego> Hey I'm reading 23kΩ resistance on the test points labelled GND and 5V (and 3V.) Is that bad (as in don't try to power it up)?

15:06 <lukego> (Maybe I'm being impatient and the board hasn't tried properly since I gave it a wash...)

15:07 <d1b2> <Attie> depending on polarity, i see ~15k / ~30kOhm

15:08 <d1b2> <Attie> don't forget that there is an amount of capacitance on that rail, so you'll need to wait for the reading to stabilise (it'll likely start low and rise)

15:08 <lukego> thanks for checking! close enough for me

15:08 <d1b2> <Attie> have you turned it on yet?

15:09 <lukego> nope but ask me again in thirty seconds :)

15:09 <d1b2> <Attie> oooo crosses fingers

15:09 <lukego> going to try 5V and 50mA to start with

15:09 <d1b2> <Attie> into the VBUS test point?

15:10 <d1b2> <Attie> *VUSB

15:10 <lukego> yep: https://twitter.com/lukego/status/1318925005628055554/photo/1

15:10 <d1b2> <Attie> looks good

15:12 <d1b2> <Attie> you should see the PWR / FX2 / ICE LEDs come on, though FX2 / ICE will be dimmer

15:12 <d1b2> <Attie> U1-5 should also be lit and "dim"

15:14 <lukego> hm nothing happened

15:15 <d1b2> <Attie> with no firmware loaded, I see ~36mA idle

15:15 <d1b2> <Attie> any current draw / what is the voltage reading? (i.e: is the current limit kicking in)

15:15 <lukego> bench supply reported no current drawn...

15:15 <lukego> (shorting the leads shows action)

15:16 <d1b2> <Attie> use a multimeter, and poke the 5v & GND test points

15:17 <d1b2> <Attie> what do you see?

15:17 <d1b2> <Attie> same again for the VUSB pad

15:20 <d1b2> <Attie> you should definately see ~5v on the VUSB pad (and #1 below).... if you don't see ~5v on the 5v TP, then try these points

15:20 <d1b2> <Attie> https://cdn.discordapp.com/attachments/613461005392936961/768493826461138945/unknown.png

15:48 <lukego> I'm reading 4.987V on 5V test point and 0V on 3V3 test point

15:49 <d1b2> <Attie> ok - how about the pins above? (i wonder if you have U15 the wrong way round)

15:49 <lukego> I did reoriented about a dozen chips this afternoon, highly likely that I missed one...

15:50 <d1b2> <Attie> i heading out for a bit, but happy to help when I'm back / if others haven't stepped in

15:51 <d1b2> <Attie> re U15 - it can be difficult to see without optics / light, but the bar should be at the FX2 end, not the USB connector end

15:52 <lukego> 3&4 is showing 0V. I thnk that 1&2 is though I'm less certain that I probed it right. Lemme check U15 now

15:55 <lukego> I think that I have U15 the right way around: https://imgur.com/a/FT6UbbB

15:56 <d1b2> <Attie> yeah, looks okay

15:56 <d1b2> <Attie> now test the bottom left pin of U15 (as oriented in that photo) - should be 5v too

15:57 <d1b2> <Attie> (that's an enable pin)

15:57 <d1b2> <Attie> also worth jusy checking for dry joints, etc... (reflow / add a bit of solder)

15:59 <lukego> Right. I committed a LOT of soldering sins while hand-assembling this board one part at a time, definitely e.g. put a LOT of heat into the FPGA and FX2 and that area of the PCB, so I should give the disclaimer that there's a high risk of spending time chasing soldering bugs

15:59 <lukego> (and I'm happy to spend MY time that way but shouldn't take it for granted that others do too :-))

16:02 <lukego> yeah 5V between ground input and bottom-left pin of U15

16:03 <lukego> Maybe I'll call it a day now and in the morning I'll make another pass over the PCB looking for soldering faults, adding some solder anywhere that looks iffy

16:06 <lukego> Thanks for this help! I am using this Glasgow as an entry-point into learning soldering and electronics so it's a bit of a slow process

16:15 <electronic_eel_> lukego: now that there was no smoke with the current limited bench supply - did you try to plug in the usb? that would be the next thing I'd do once there is no smoke with the bench supply at 5V