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FMC-104 Trigger Input Questions

I have some FMC-104 modules that I'm using to measure the charge in the Advanced Light Source storage ring bunches.  This is working well, but I'd now like to use the trigger input as well.  I can see the signal making it on to the board by looking at the connector solder point with an oscilloscope.  But the signal read by the ML-605 FPGA is always 1.  Is the FMC-104 documentation showing the trigger to FPGA on LPC connector pin G37 correct?


I double checked the trigger connection to the FMC connector and it connects indeed to G37. Probably your ML605 sets VADJ to 2.5V? For this voltage level, trigger input Vih > 1.7V and Vil < 0.7V, with a input voltage range of 0V to +5V. Could you double check that you apply to correct voltage? Is the FMC104 plugged onto the LPC or HPC connector of the ML605?

Best regards,
Ingmar van Klink

Yes, the FPGA I/O pins are configured as:
[size=10px][font=Monaco]NET TRIGGER_FROM_FMC LOC = "K31" | IOSTANDARD = "LVCMOS25";[/font][/size]
The signal at the printed circuit board pin of the "TR" SSMC connector is a pulse starting from <0.1V, going to 2.5V for about 100 ns, then returning to <0.1V.
I am using the ML-605 LPC connector (J63).
Perhaps I have a broken ML-605 or FMC-104.....
Tried a different ML-605.  I see triggers.  Must have been a bad unit.
Sorry for the bother.
    and thanks for the quick reply!

Dear Sir,

Thank you for the feedback! Feel free to create new topics when you need to do so.

Best Regards,
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