Need safe register for URC-8810w w/ Extender 3.1

ti83programmer · Post by **ti83programmer** » Sun Nov 23, 2003 11:16 am

I'm really interested in S3C8 assembly, and I'm close to a new special protocol (a worthless one, but nevertheless my first), and I need a safe place to store a number. With all the other protocols and the extender using all these registers, I'm all confused as to where I can go. Do you know of a spot in the memory I could use? Thank you!

ti83programmer · Post by **ti83programmer** » Sun Nov 23, 2003 4:50 pm

By the lack of replies, I'll assume that question was too broad to answer. I was asking for a place like RC5, RD9 or something like that. If it is, could someone tell me so I can clarify?

Mark Pierson · Post by **Mark Pierson** » Sun Nov 23, 2003 5:15 pm

ti83programmer wrote:...I'll assume that question was too broad to answer...

Or, most likely, the people who can answer haven't seen this post yet. After all, it is Sunday, and not everyone checks in on a regular basis over the weekend. Give it a little more time...

BTW, I moved this over to the Extender forum since it's not really a general question.

Post by **The Robman** » Sun Nov 23, 2003 5:45 pm

The main people qualified to answer are John, Hal and David (and a few select others) How long do you need the data kept? Is it only used while the protocol is running (in which case one of the RCx registers might suffice) or do you need it kept around after the protocol has stopped?

I didn't notice at first but he states what remote he's using in the subject, it's a URC-8810

vasqued2 · Post by **vasqued2** » Sun Nov 23, 2003 7:42 pm

I haven't looked at the 8810 extender for v3.1 in detail so I'll give a couple of general ideas first. If this isn't enough to get you started, just let me know.

Rob's right, if you are only looking for temporary storage, one of the RCx registers should be fine.

If you are looking for something more persistent, another easy answer would be to find a register that is already reserved for some functionality that you aren't using. For example, if you don't use the ToadTog special protocol, RB0 would be available. You could also shorten the macro buffer by one and use that extra byte.

Finally, it's probably reasonably safe to use one of the other RBx registers. Some of the newer remotes use some of them but if you're feeling lucky, pick one and see how it goes. The fact that ToadTog uses RB0 is a good sign that the others will be available. John is more familiar w/ the 8810 and can let you know there are some that you should avoid.

Hope this helps and good luck.
David

ti83programmer · Post by **ti83programmer** » Mon Nov 24, 2003 7:24 am

I'm sorry for getting a little too excited there, I'm used to people answering quickly. I do need this for storage outside of the special protocol. I took a look at the ToagTog protocol and saw RB0, and I'm giving that a shot (I don't use ToadTog). Thanks!

P.S.: By the way, the reason I wanted this was because I want a random number routine. I know nothing about how random number routines work, but it made sense to me to just jump around at different points in the memory, based on values from previoous jumps, and then getting the value at that address and using that number. Is it stupid, or even possible? Maybe I'm trying to do something that simply can't be done.

johnsfine · Post by **johnsfine** » Mon Nov 24, 2003 7:36 am

Registers above RBF are treated specially by the cpu. You should read the Samsung documentation for details, but basically you can't use them for data storage.

If I remember correctly, the 8811 family does not use any registers between the end of the macro buffer and RBF. The extender increases the size of the macro buffer, so it extends from R80 through R9F. That should leave RA0 through RBF free for use by special protocols, but I haven't checked that carefully. As noted above the ToadTog bundled with the extender uses RB0. I'm not sure what other special protocols exist nor what registers they uses. Probably you're not using any others.