Re: TI-H: Back to basics


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Re: TI-H: Back to basics




Christopher Kalos wrote:
> 
> Okay, here we go again...  no more non-TI oriented stuff.
> 
>     For the EII, is there a plan to go back to MMODs now that the device
> is completed?  I guess this is more Rich's department, but still
> important.

Yeah, as long as the physical connections are made and wire lengths are
kept short it is really up to you how you build it.

>     On the schematics, I noticed one thing missing.  A clock signal on
> the module port.  Am I wrong, or is that just the way it was meant to
> be?  I always thought that a clock signal would be helpful. :)

Uhh, if you really need it you can generate a clock on any of the lines
by using the mod port write op code and a z80 interrupt. All 6 module
port lines are totally generic digital I/O now... I removed all special
functionality in favor of offering more flexibility and more reliable,
faster operation.

>     Another thought: shift registers and a DAC...  possibly set up four
> bit sound, which isn't great, but it beats the current speaker designs.
> I was thinking only four bits in order to save memory while adding to
> the audio quality enough to make it bearable.  This might also mean that
> we can think of using the TI for a bit more fun without a serious hack
> job, which, as Mel says, is not something that most ppl are willing/able
> to do.
>     Other important hacks:  Oh, forget it, I'll just use the frigging
> EII module port.... what is that, six lines?  add the clock signal, and
> we can probably pull off RS232 as an afterthought.

Nope, sorry. I did have the ability to write RS-232C to two specialized
lines in some of the beta firmwares. However, letting the calculator
control
the bitrate over a large range would be fairly difficult. I do have
serial routines working, but for now I would rather leave the module
port
as 6 vanilla I/O lines rather than four lines and two dedicated to
RS-232C.
So, the E2 will not give you RS-232C. I may freely release another AVR
.HEX file that converts TI to 8N1 9600, however. Its really not too
difficult,
but it is not terribly useful as it will not replace a graphlink. Has
anybody
hacked the graphlink to figure out exactly what its doing yet?

>     And by the way, TI's can go wireless...  for about $400 a calc.  The
> wireless IP Minstrel modems (www.novatelwireless.com) work with a
> graphlink/broken pilot connector and everything else, or do I've heard.
> But guess what?  No amount of expertise will make that type of design
> any cheaper.  Therefore, I'm not going to test it.  I forgot to bookmark
> the page and now I have to track it down again... oops :(

A few months ago (probably more like a year) a surplus place in CA that
advertizes in Nuts and Volts offered a pair of 38400 baud radio modems
with all the goodies for $50... yeah, that's right, $50. I managed to
get my hands on one pair, but after that they dried up. I understand
they
still get frequent calls requesting them, but when surplus is gone, its
GONE. They work great, and I think I got quite a steal... I understand
that commercial radio modems are EXTREMELY expensive. If you don't
already, you may want to check out nuts and volts, its a great mag...
http://www.nutsvolts.com/

I may try to get an article published in there around the end of the 
year, so you all better go subscribe :)

Regards,

Bryan 
"Why should the college boys have all the fun?" :)

-- 
Bryan Rittmeyer
mailto:bryanr@flash.net
http://www.flash.net/~bryanr/


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