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CFA_533 - Command 4 (Store Current State as Boot State)


New member
We are trying a small batch of 533 modules in a new product. We are using exactly the same command set as on the 633, which we have used on other products for several years. The 533 modules are working fine, except in one respect, which is that we can't update the welcome message.

As delivered, the displays report the standard Crystalfontz welcome message, but once we try to use Command 4 (Store Current State as Boot State), the welcome message becomes a series of spurious symbols.

We are using exactly the same routines as on the 633, which still works fine in this application.

We are running from a 3.3V supply,which we believe is in spec.

The symptoms suggest there may be a problem with the 533 hardware/firmware. The hardware type is CFA_533 YYH KL, v1.0 and the serial number of one of the units is 1009533YYH0006060. We don't currently read the firmware version in our application firmware, but I can arrange to do that if you can't trace it from the serial number.
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CF Tech

We came across this once before.

The microcontroller cannot read the LCD correctly at the low voltage, so it reads and stores garbage.

I will make sure that this note gets in the data sheet--(it should already be there, I am not sure how we missed that).

I can think of two fixes:

1) temporarily supply 5v to the module during the boot screen save operation

2) We can set up a semi-custom part number (defined part or DP) that will specify the boot screen, so the module will have the boot screen you want when you get the module.


New member
Thanks for your quick reply. I was wondering if it might be a power supply issue (we occasionally get them too!).

Now we know, we might be able to work around it. Our hardware is designed for 3.3V, but we might be able to use 5V during the factory setup process.

Another thought: do you have an adapter that allows the 533 to be connected to a PC (RS232 or USB)? If so, maybe we can use one of your utility programs to set up the welcome message.

CF Support2

It is possible to interface your CFA_533 YYH KL to a PC via USB or a full swing RS-232 COM port. We would need to set you up with either a USB daughter board that we used on our v1.5x CFA633 modules, or adapt one of our CFA-RS-232 boards we use on our CFA635 series modules.

The USB daughter board would be a much cleaner solution as it is designed to work with the 10 pin 0.100" header.

If you send an email to support@crystalfontz.com - we'll get a ticket going and get you taken care of.


New member
Thanks for your help on this. I have sent an email to support@crystalfontz.com.

I have a follow-up question. We also write to the User Data area during normal operation. Is the data we store there likely to become corrupted for the same reason?