7i76e - TB2 not working - no axis motor movement - but TB3 and rest working fine

The picture is frim my Gecko201x the image is from internet
201X the wires i labeled Y1PU- (step -) Y1D- (dir -) and Y1D+ (common)
Do what Mike told, check your pins.

Thank you guys for your help.
I will later check the pins as Mike described and let you know what i found out.

I was looking for the correct chips (both TSSOP). Hope you can tell me if that are the correct ones.
MC74ACT540DTR2G
MC74ACT541DTR2G

So i just measured all pins from all step generators when toggled and not toggled.
I will not write down all values/results but here what I did first:
I measured on the one step generator from TB3 and wrote down the results when measured against GND and then from again 5V.
The step generator on TB3 is working as you know, so when toggled it drops from 5V to 0V or from 0V to 5V (depending on which pin i measure).
This behavior does not happend on all step generators from TB2.
Their I get instead of 5v only 4.84v and when I toggled it drops to 4.6V (when measured again 5V)
When measured against GND then I get 0.59 and when toggled the voltage raises to 0.135.

Even if it might not look pretty clear as I wrote it, i think you see the difference.

Now, am I correct that I cannot use any of those pins from TB2?

I think pcw only can give you a definitive answer, but i would guess NO.

What i'm not sure about if there is a way to use stepper hal.pins and copy them via hal to normal outputs.. (regard different voltage so you do not burn your drivers inputs) maybe this could work for slow movement.
Also, a bit risky methode, with a different 7i76e firmware you might get more steppers and use p1 or p2. But here as fare as i understand you have to be very carefull and use level shifting.
Best is to wait and listen to pcw's advise..
Mike

Yes Mike I thought about the same, but I thought about a other quiet quick solution.
I could add a cheap pci BOB and use it to for the second motor (I have 2 cheap bobs here and a cable)
The thing is only that I could need some advise how to add the pci card to the 7i76e hal file. Is there maybe somewhere a example config of a combination of e.g. 7i76e and a pci card with a breakout board?

denhen89 wrote:

Thank you guys for your help.
I will later check the pins as Mike described and let you know what i found out.

I was looking for the correct chips (both TSSOP). Hope you can tell me if that are the correct ones.
MC74ACT540DTR2G
MC74ACT541DTR2G

Those are correct

Exactly a minute ago my friend who replaced already one chip on the card told me that that are the correct ones but nice to hear that also from you.
Thank you PCW

Ivm not sure if this is a good idea.
Stepgen via lpt has latency problems in preempt.

1. But it should be easy to make a new stepgen based testconfig.
See first with that if your pci cards run under that os at all. Only if yes:

2. Exclude the part for the pure 1 or 2 stepgens, including base thread.
3. Copy your mesa config
4. Combine in the copy both parts, and comment out not runing mesa stepgen.
Adapt lpt stepgen to missing axis....

All in all quite some work... I would not do it.

Better ask pcw if a p1 or p2 stepgen could handle a lpt-bob.

Or saver: have some time with family and wait your friend to repair your board.
And order in the meantime a spare one (i always have at least one spare of important parts. Thats why i have in the sence of Murphy too much not used components. ;-()
Mike

You can use an external LPT type breakout by
flashing the 7I76E with firmware like 7i76e_7i76x1_5abobD.bit
that supports 5 additional stepgens on the first expansion port
wired for the common "Mach 5 Axis BOB"

Hi pcw
Just for my curiosity.
Do i understand correct that this pinfile uses the signals in a kind of mixed mode:
The 5 steppers use 10 native step/dir out pins. Similar are the 3 encoder in pins. The rest of possible signals are "transfered' via sserial.
Plus that you have to make a special cable if you want to use a Chinese bob. I also guess that this must be 3.3v compatible and probably should only have the stepper signals cabled. And isn't there a risk that drawing to much current destroys the 7i76e fpga?
Thx in advance
Mike