32KB RAM on 84+SE???

mnc2fan · Post by **mnc2fan** » Mon 22 Aug, 2005 6:34 pm

I was looking inside my 84+SE and I looked at the RAM chip and on it there are numbers 32.768K. I don't have a good enough camera to take a picture, but...

84+SE

83+SE

That might not even be the ram chip, but I think it might be. Don't know about the 83+SE but my 84+SE has those numbers on it, so does that mean that there is a way to expand the RAM. So anyone with the 83 or 84 SE can see what I'm talking about.

Jim e · Post by **Jim e** » Mon 22 Aug, 2005 6:39 pm

That's the crystal timer, it runs at ~32.768khz. I'd take pictures of my calcs but I don't want to risk ESD just yet.

Edit: Also remember that SE have 128 k ram. And there is a good some of hardware that would prevent any ram expanision from being useful or easy.

mnc2fan · Post by **mnc2fan** » Mon 22 Aug, 2005 6:47 pm

Wow I'm still learning...

. So what does the crystal timer do, does that have something to do with the cpu, or something else.

Post by **Dwedit** » Mon 22 Aug, 2005 7:02 pm

The TI83+SE's ram is already upgraded, I think to 128k. It's just that nobody has used it yet.

Jim e · Post by **Jim e** » Mon 22 Aug, 2005 7:06 pm

WikiTi has a few answers.

They are seprate timers from the cpu clock, they can generate interrupts at almost any frequency. I use them for the greyscale and sound things I did. Or they can be used simply for timing, i've used them quite a bit recently to try crack some of the unkown ports.

Edit:

The TI83+SE's ram is already upgraded, I think to 128k. It's just that nobody has used it yet.

Omincalc used it for virtual calc and ram restore. Plus ti-os uses them for the usb.(that's what dan said anyway.)

Post by **DarkAuron** » Mon 22 Aug, 2005 8:14 pm

The RAM pages are 16kb each, and you normally have about 24k free if you're not taking up anything. 8kb is taken up from the TI-OS... so yes, 32kb sounds right. But the SE should have 128kb, so... yeah

And the extra ram has been used in omnicalc.. kindof.

Gambit · Post by **Gambit** » Tue 23 Aug, 2005 4:39 am

DarkAuron wrote:The RAM pages are 16kb each, and you normally have about 24k free if you're not taking up anything. 8kb is taken up from the TI-OS... so yes, 32kb sounds right. But the SE should have 128kb, so... yeah And the extra ram has been used in omnicalc.. kindof.

This is "common knowledge," but ever wonder why a fresh RAM reset is only 24384B (more or less), not the full 32K? If you know your memory architecture, you know that RAM spans from $8000 to $FFFF in memory. And, the start of RAM (a.k.a. userMem) is at $9D95. Thus:

Code: Select all

$9D95-$8000 = 7573d

But wait, there's more! The VAT and the various stacks also take up the end of RAM. Cheating a bit:

Code: Select all

$FFFF-$9D95-24384d=810d

Thus, 810 bytes at the end plus the 7573 bytes at the beginning is 8383 bytes, and that's where the 8K comes from.

mnc2fan · Post by **mnc2fan** » Tue 23 Aug, 2005 5:14 am

So basically, it would be use less to have that RAM available to the user since if that part was filled with user data the OS wouldn't have any RAM to use for its own.

Well those numbers could possibly be the frequency of the crystal timer and by coincidence also be the same amount of RAM the calc has in total. Do you know what the OS uses that 8 Kb of RAM other than stacks?

Jim e · Post by **Jim e** » Tue 23 Aug, 2005 5:33 am

Tios needs 8k to run, but it has quite a bit of free ram as well, around 3k You could rearange the memory so yuo have continuos 3k of mem free to use, but the you need put everything back when your done(and not use interrupts or bcalls). but yeah you can't give the user that mem, ti-os needs it.

That little chip is the cyrstal timer it has only 4pins, you can't addrres much with that. And there is no coincidence the calc has 128kb of ram not 32kb. It's just that 96kb spends most of it's time sitting there looking pretty.

Flags, hooks, screen data, calc settings, and maybe some other stuff.

Kalimero · Post by **Kalimero** » Tue 23 Aug, 2005 7:51 am

On the 83+se the ram chip is the smaller one of the two chips on the left. On the 84+, the ram is inside the asic (application specific integrated circuit) with a lot of other stuff (z80, usb controller,...).

mnc2fan · Post by **mnc2fan** » Tue 23 Aug, 2005 5:13 pm

I finally found out where all the RAM and USB controller, and Z80 is when I looked up what the asic chip was, basically system on a chip.

lecks · Post by **lecks** » Sat 10 Sep, 2005 6:46 pm

all of your answers should be here: http://en.wikipedia.org/wiki/TI-84_Plus_Silver_Edition

currahee · Post by **currahee** » Sun 11 Sep, 2005 4:07 am

Jim e wrote:WikiTi has a few answers.

They are seprate timers from the cpu clock, they can generate interrupts at almost any frequency. I use them for the greyscale and sound things I did. Or they can be used simply for timing, i've used them quite a bit recently to try crack some of the unkown ports.

Edit:
The TI83+SE's ram is already upgraded, I think to 128k. It's just that nobody has used it yet.
Omincalc used it for virtual calc and ram restore. Plus ti-os uses them for the usb.(that's what dan said anyway.)

No, not USB. THat can't be right. 84+ calcs only have 32KB

Jim e · Post by **Jim e** » Sun 11 Sep, 2005 4:13 am

I'm pretty sure that 84+ is running on the same asic. Remember ti shows 32k.

currahee · Post by **currahee** » Mon 19 Dec, 2005 9:02 pm

I asked the same thing on Detached. Michael Vincent sure knows his thing. He confirms that the 84+ does indeed have 128KB of RAM.

http://www.detachedsolutions.com/forum/ ... php?t=2611