Re: [M100] REX build failure - post mortem

That's exactly why I want to come up with a little saner way to pull up PORT_EN. It's way too easy to just touch the wrong side of that resistor, or something else in the area. It's begging to happen some percentage of the time even if you know what the problem is and are careful. On Wed, Oct 18,

Re: [M100] REX build failure - post mortem

Josh, I looked at one of the REX boards I had that didn't work. The regulator was getting hot on it and I had the same low resistance measurements on the VCC and ground. I know on this particular one I killed the CPLD by shorting the FTDI VCC and ground when jumping VCC to R3. Brian On Oct 18,

Re: [M100] M200 and bad RAM??

A T200 with a clean memory should show around 19K per bank, if they are fully populated. Part of the 24K is taken up by the system so it is not all available for the user. Just a thought have you tried to power on while holding ctrl-break to make sure nothing has been left in memory from some

Re: [M100] REX build failure - post mortem

Josh, my suggestion would be that, short of a board defect which is rare but can happen, you have a solder bridge underneath one of the chips. You also can have a chip soldered in the wrong orientation. that would make a big problem. Steve On Wed, Oct 18, 2017 at 12:47 PM, Josh Malone

Re: [M100] REX build failure - post mortem

Thanks. I tested an unpopulated board and it showed no issues w/ power traces. It must be something I did, but it seems that it must have been under one of the ICs. Bugger. Will have to depopulate them and check. Thanks! On Wed, Oct 18, 2017 at 1:22 PM, Stephen Adolph

[M100] REX build failure - post mortem

All, So, I just let the magic smoke out of my third REX build. Not sure exactly what went wrong yet. Hoping for a bit of help investigating. 1) Has anyone built a functional REX with the pre-castellated boards from OSH park. I don't think this is the problem, but hoping to verify 2) Can

Re: [M100] REX build failure - post mortem

If you actually smoked the chip as you said it will be a dead short. Most ICs will fail dead short on their power rails if there is an issue like reverse voltage. Jerry On 18 October 2017 at 12:40, Josh Malone wrote: > Thanks. I tested an unpopulated board and it showed

Re: [M100] REX build failure - post mortem

11.7k on 2 of mine. On Oct 18, 2017 4:25 PM, "Stephen Adolph" wrote: > I can try to measure it later today for you. > > On Wed, Oct 18, 2017 at 4:24 PM, Stephen Adolph > wrote: > >> either the chip is a dud, or you have soldered it down in the wrong

Re: [M100] REX build failure - post mortem

Thanks. I'm going to just order new parts and try again. On Wed, Oct 18, 2017 at 4:49 PM, Brian Brindle wrote: > 11.7k on 2 of mine. > > > On Oct 18, 2017 4:25 PM, "Stephen Adolph" wrote: >> >> I can try to measure it later today for you. >> >> On Wed,

Re: [M100] REX build failure - post mortem

Thanks for the leads. I removed the CPLD and the resistance from 3v3 to gnd went to open; repopulated it and it went to 3-ohms. Dunno what to try next. Maybe put the same CPLD back on an original REX board (non-castellated) and see what happens. But, I'd *really* love for someone to measure the

Re: [M100] REX build failure - post mortem

I guess if you're going to build over 60 of them it starts to matter. I just figured if I'm going to go to this much effort it took just to build one at all, that $1 wasn't even visible, but a built and in-use rex that fails some day when it might have lived, is visible. So I went for the

Re: [M100] REX build failure - post mortem

Orientation is correct. I suppose I might have fried it before. Funny thing is that I measured proper 3.3v at the jtag header yesterday but didn't have my programmer handy to flash it. Today I tried to program the CPLD and it smoked. I must have just buggered something up good. Or, like you said,

Re: [M100] DVI cable

I'm not sure this made it the first time; apologies if it's a duplicate. -- What may not be obvious is that the 'swapping cable' (i.e. a 'normal' F-F 40-pin cable with double-ended pins inserted in one end) is also effectively a T102/T200 cable; no need for that tedious

Re: [M100] REX build failure - post mortem

Commercial is fine On Wednesday, October 18, 2017, Josh Malone wrote: > Also, meant to ask: > > Brian's BOM includes the Industrial variant of the CPLD. The > commercial variant is almost $1 cheaper and seems well within > tolerance > > (voltage min is 3 instead of

Re: [M100] REX build failure - post mortem

I can try to measure it later today for you. On Wed, Oct 18, 2017 at 4:24 PM, Stephen Adolph wrote: > either the chip is a dud, or you have soldered it down in the wrong > orientation (which is kinda easy to do)... Do you have more CPLDs? > > On Wed, Oct 18, 2017 at 4:22

Re: [M100] REX build failure - post mortem

either the chip is a dud, or you have soldered it down in the wrong orientation (which is kinda easy to do)... Do you have more CPLDs? On Wed, Oct 18, 2017 at 4:22 PM, Josh Malone wrote: > Thanks for the leads. > > I removed the CPLD and the resistance from 3v3 to gnd

Re: [M100] REX build failure - post mortem

Also, meant to ask: Brian's BOM includes the Industrial variant of the CPLD. The commercial variant is almost $1 cheaper and seems well within tolerance (voltage min is 3 instead of 2.7, temp is 0 - 70 C instead of 40 - 85 °C) Any reason not to sub this part in? -Josh On Wed, Oct 18, 2017

Re: [M100] DVI cable

I really like that idea. Make a regular M100 cable by insuring that your DIP IDC connector is one that connects pins the right way to allow simply crimping straight through to the DVI connector. And service T102/200 by adding an adapter which also needs nothing but normal crimping. Then your

Re: [M100] Model 200 and TPDD2

I tried again this evening and it seems to be working! Weird indeed. Thanks for replying. On 18/10/17 00:03, Kurt McCullum wrote: > NM is a "bad file name" error. > > Make sure the write protect is set on the floppy disk. Turn off power to your > TPDD2, then type RUN"COM:98n1enn" from BASIC

[M100] M200 and bad RAM??

I just noticed this evening that my M200 is only showing approx 5000 bytes free with nothing in memory (can't remember exact figure as it's now open). I thought it was supposed to have 24K but could be wrong. The memory board has 3 x HM6264LP modules. Are they all used and is it possible one or