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Problems getting 631 to work with ATX controls


New member
I have a CFA631-USB (PCB V2.1 RoHS) + CFA_SCAB (PCB v1.1) board that I am attaching to a Tyan S2912 motherboard. The 631 display shows HW 2.0 and FW 2.0 upon boot.

I want to run this with ATX power control and as such have done the following:

-Connected floppy power connector attached to J3 (Switched power)
-Disconnected JP8
-Shorted JP9
-Connected motherboard ground to the ground pin of J8
-Connected Vsb from motherboard to +5V pin of J8 (S2912 motherboard has motherboard header support for a Tyan front panel LCD, (J113) that provides among other things ground and Vsb)
-Connected PWR SW+ to GPIO2 of J8
-Connected Reset SW+ to GPIO3 of J8

-Disconnected JP2
-Using 631_WinTest the board is set to ATX control, values set by sending command 28, 34 and then 4.

This all doesn't work in ATX mode. I no not seem to get any GPIO triggers for the power on or reset lines. The big tip-off that something is not set up properly is that I am not getting screen blanking when the unit is powered off. The logic is supposed to be that when it is in ATX mode it monitors the Power-on Sense line, GPIO1, and if +12V is not present but Vsb is present then the front panel LCD will be blanked to simulate the power off condition.
The LCD powers on with only the only ground and Vsb applied to the SCAB. (i.e. I can disconnect all of the other cables like USB cable and floppy power connector.)

When I attach the floppy power connector and USB connector and measure voltage on GPIO3, GPIO2 and GPIO1 respectively then I get 0 V, 0 V and 275 mV. When I measure the resistance across GPIO3 and GPIO2 they both measure out as high impedance regardless of any combination of key pressing and holding of any for the front panel buttons.
Using 631_WinTest I can trigger GPIO functions an they work properly in powering down and rebooting the machine but something is not attached, configured or running properly to get the ATX functionality to work.
I am able to use the display functions properly and I have verified that the front panel buttons are operating properly in 631_WinTest.

Any advice or information of things I can check on to troubleshoot this issue?
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CF Support

What data did you send for command 28? 240 is the most common, but other variations are required for some motherboards power/reset pulse direction.
USB LCD Displays - Graphic and Character LCDs with a Keypad