LinuxCNC-RIO - RealtimeIO for LinuxCNC based on FPGA (ICE40 / ECP5)

meister wrote:

All my positive terminals are connected to the purple cable via a thin wire.

Dirhold isn’t the problem; it really is the voltage that’s coming through – there was a clear difference between 3.3V and 5V.

My connections are like in your image, but with EN connected.

You could use a multimeter to check what voltage is coming through your DIR pin.
 

I suspect that when the DIR signal starts acting, it might not follow the set dirhold wait time, outputting PULSE before the process is complete. When encountering a motor driver with a slow dirhold response, this results in an invalid PULSE output. It's strange that increasing the dirhold value doesn't solve the problem; this is a problem I don't understand.

viewsat wrote:

meister wrote:

All my positive terminals are connected to the purple cable via a thin wire.

Dirhold isn’t the problem; it really is the voltage that’s coming through – there was a clear difference between 3.3V and 5V.

My connections are like in your image, but with EN connected.

You could use a multimeter to check what voltage is coming through your DIR pin.
 
I suspect that when the DIR signal starts acting, it might not follow the set dirhold wait time, outputting PULSE before the process is complete. When encountering a motor driver with a slow dirhold response, this results in an invalid PULSE output. It's strange that increasing the dirhold value doesn't solve the problem; this is a problem I don't understand.
 

You can check that Dirhold is working using Testbench and by monitoring it on an oscilloscope or logic analyser.
It worked for me with the default settings, but it’s certainly better to set it to the manufacturer’s specifications to be on the safe side.


(cd riocore/plugins/stepdir/ ; make)



In my tests, the problem only occurred at 3.3V;
if you Google ‘DM542 problem’, you’ll find lots of reports of the same issue.[/quote]

meister wrote:

viewsat wrote:

meister wrote:

All my positive terminals are connected to the purple cable via a thin wire.

Dirhold isn’t the problem; it really is the voltage that’s coming through – there was a clear difference between 3.3V and 5V.

My connections are like in your image, but with EN connected.

You could use a multimeter to check what voltage is coming through your DIR pin.
 
I suspect that when the DIR signal starts acting, it might not follow the set dirhold wait time, outputting PULSE before the process is complete. When encountering a motor driver with a slow dirhold response, this results in an invalid PULSE output. It's strange that increasing the dirhold value doesn't solve the problem; this is a problem I don't understand.
 




You can check that Dirhold is working using Testbench and by monitoring it on an oscilloscope or logic analyser.
It worked for me with the default settings, but it’s certainly better to set it to the manufacturer’s specifications to be on the safe side.


(cd riocore/plugins/stepdir/ ; make)

In my tests, the problem only occurred at 3.3V;
if you Google ‘DM542 problem’, you’ll find lots of reports of the same issue.

I apologize for asking so many questions. I always use 5V to power the 74HC245 and the driver. If there's a problem, usually adjusting the DirHold time is all that's needed. When I use a Mesa 7i92 + 74HC245 (5V) + DM542 (pulse=10, DirHold=25), everything works perfectly, and it correctly returns to the zero position. However, when I switch to a Tang Nano 9k+ + Riocore + 74HC245 (5V) + DM542 (pulse=10, DirHold=25), it fails to return to the zero position, and adjusting the DirHold time doesn't help.