CFA635 firmware 2.0 issue


New member
I have 2 different CFA635s one with the 1.6 firmware and one with the 2.0 firmware.

My code works perfectly on the v 1.6 model. On the v2.0 any command with a data length greater then 0 will cause the display to blink and reprint the startup screen. The example code in the linux_cli_examples also will not work with the newer firmware/controller.

Has anyone else noticed this? Is there a known solution?

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CF Support

Thanks for your message.

What distribution of Linux are you running? Is it 64 or 32 bit? Can you send your code that is causing the described behavior?

If you can't post it here, you can email and create a ticket so we can handle this in a non-public fashion.

Please let us know.


New member
I am currently using CentOS 2.6.32 kernel. 64bit.

Thinking this may be a 32/64bit issue, I downloaded the Crystalfontz 635 WinTest v1.0 software on 32-bit Windows. No dice!
The program recognises the display. I can clear the screen and adjust the backlight and contrast, when I try and send a Line of text, the screen blinks and brings up the startup screen.

CF Support

CFA USB Reprogram

We have identified and fixed an internal process error that allowed a batch of CFA635 modules to be shipped with incorrect FTDI settings. This incorrect setting can manifest itself in many ways including odd flickering, not writing text to the screen, dimming the backlight and/or contrast, and going into infinite reset. We have determined the root cause of this issue. A GPIO pin on the FTDI chip of the module has a pin was set to an incorrect state.

We apologize for this inconvenience but have good news, this can be resolved without any hardware adjustment or shipping required. Our software engineers have written a solution to reprogram the FTDI chip simply by running an executable. Please see the attached file.

This requires running the Self-Extracting executable on a windows 7 PC and will unzip the contents into C:\CFA. Follow the instructional PDF document in the extracted folder to install and run this fix.

Thank You