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Migrating from CFA634 NFA KS to CFA634 TFH KS0


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I have used the CFA634 NFA KS with non-inverted serial logic levels for many years with no problems. This screen was discontinued and I just received a batch of new CFA634 TFH KS0 screens (the closest match) and I am having a difficult time configuring them for logic level use.

On the old screen (CFA634 NFA KS) I only had to change the two dip switches and short JPE and JPK. From the preliminary datasheet for the new screen (CFA634 TFH KS0) it seems that it can no longer be configured with switches and jumpers only but must be configured using commands send via the serial or USB port. So what is the right procedure?

This is what I am doing:
1) connect screen DB9 to a serial on my computer and apply 5V to the +5V LCD pin in J2. The serial port alone is not able to power the screen. Screen boots up fine with the Crystalontz logo and misc. text. All Wintest demos work fine.
2) Use wintest so send the command \009\002\004 (logic level serial - noninverted)
3) send \009\003\003 for 19.2kbps port speed
4) send \009\001\001 for user screen (I suppose this is to disable the boot screen)
5) send \009\005 to save (not sure about this one)
6) short JP3 and JP4
7) open JP5 and JP6
8) open JPBL so no backlight for the test.
9) connect MOSI in J2 to microprocessor, keeping the 5V and ground power lines.

The result is a garbled screen or no communication at all. Unfortunately to change any settings I have to reconfigure the JP3 to JP6 jumpers for full RS232 and the test screen is not fairing too well after many solder - resolder cycles. Maybe a USB cable can make configuring the screen easier?

Any help would be appreciated.
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New member
Got no replies so I though I update this:

I got it to work after I jumped JP3 and JP4 and opened JP5 and JP6 and used cftest with the USB cable to send the programming commands. I had to use XP in VMWare because the screen's USB interface will not work on Windows 7 or 8.
Last edited:
USB LCD Displays - Graphic and Character LCDs with a Keypad