SY41CL-- Updating YFNZ-2B to YFNZ-3B


To all those 41CL experts out there...

Any need (or even any point) in upgrading V2 hardware to YFNZ-3B? Will it work and will I gain anything? Actually my thought was to simply put the ROM on a NoV-64 module I have coming and use it that way rather than to risk messing with the 41CL's internal ROM.

I did several searches and didn't find anything on this particular subject but maybe I am looking in the wrong place so if the information is available I'd appreciate someone pointing me in the right direction.




YFNZ-3B will work on the V2 hardware as long as the Image Database is present in Flash (it's only missing by default on the Beta boards).

-3B cleans up the error handling and user messages, which isn't really a big deal. It also adds the missing check for writes to the OS area of Flash, to prevent the accidental overwriting of that area of the Flash. If you don't write to Flash a lot this isn't a big deal.

In -3B the PLUG functions use the Image Database, so that it is possible for you to add mnemonics to the database if you want. I don't know of anyone who has done this yet though.

Bottom line is, it's not a critical update for most users.


Thanks Monte,

I did read about those changes in the notes on the CL page. I was wondering if there were any other changes and it looks like there is nothing new I need at this time.




I forgot to mention that in -3B some of the functions, ike YMCPY and YFWR, automatically execute at 50x speed and then restore the previous Turbo state so that the user doesn't have to remember to do this.


Hi Monte,

Now that I have not seen elsewhere and *IS* worth upgrading for! I use the YMCPY command a fair amount and while I now have programs to handle most cases I use frequently that added automatic speed increase feature is really nice!




I don't know of anyone who has done this yet though.

Hope to be able to work on that soon...


The thing to remember is that the Image Database is set up so that you can write to unprogrammed individual database entries. Of course, you'll need to dissect the YFWR function to see how to unlock Flash writes, but otherwise it's straightforward.

If you don't want to go that route, you can also fill a 4K RAM block with 0xFFFF, poke the new values you want into the appropriate RAM locations and then do a YFWR of the RAM block to the Image Database. This will work because writing ones to already-programmed Flash locations has no effect. It's just that this route will obviously take longer to execute.



V2 hardware schematic is dated 12/10/2010 on the website.

So, is it safe to assume that the beta boards are V2 (V1 being the alpha boards) ?

If yes, can we beta guys first write the Image Database to flash and then write YFNSZ-3B to a free flash sector ?

Then, if this works fine, will the old YFNZ-1A in the OS-area still work when we fully reinitialize the CL board ?

Sorry, many questions, but I want to be sure before proceeding with the upgrade.




Yes, Beta boards are V2. YFNZ-3B can be used on any board as long as the Image Database is present in the correct location. The functions PLUGH and PLUGP won't do anything on a Beta board because the underlying FPGA programming didn't support MMU operation for Pages 5 and 6. YFNZ-1A in the OS area will still work fine, because it uses internal hard-coded addressing to find the Image address. Of course you'll probably need to PLUG the YFNZ-3B into a Port using a direct address (unless you choose to use one of the XXX mnemonics).


Thank you Monte !

This looks like a next week-end job :-)

I fully appreciate that it is forbidden to write to the OS area...but...

If YFNS-2B still allows us to do so as stated in the release notes, would it be possible :

- from my YFNS-2B in RAM : to write YFNZ-3A *to the OS area* (therefore obliterating YFNZ-1A)

- and then to flash Image database and YFNS-3A to normal user flash

Yes, I know: *dangerous* and *risky*. it possible ?

this would allow me to have YFNZ3A handy with my favourite XROM even after reinitializing the board.



Edited: 12 May 2012, 3:37 p.m.



Remember that the Flash is erased by sectors, which means that you'll erase all of the OS in addition to YFNS-2B! At that point your calculator is a brick!

NEVER try to write to the OS area. That's why there was supposed to be an inhibit for this in YFNZ.


Ok, I won't ! I promise :-)

Ah yes, flash erased by whole sector...sigh :-(

Thanks again for all the magic, Monte.


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