ezf@bbncc5.UUCP (Ed Frankenberry) (05/03/86)
I finally located a Logo II cartridge for the home computer. Trouble
is, I can't even get started using it with only 16k memory (the title
screen says "check system"). Looks like I'll need to build a 32k
memory expansion board. Before reinventing the wheel though, has
anyone else homebrewed some add-on memory? I haven't seen any cook-
books on how to interface with the 99/4a "bus", but maybe someone else
has. Have there been any articles on expanding a bare-bones system?
Are schematics still available for the TI expansion box and cards?
Even the TI literature (9900 Family Architecture) seems to be
out of print and discontinued.
Thanks,
Ed Frankenberry
usenet: {ihnp4,decvax}!bbncca!ezf or ...!bbnccv!ezf
internet: ezf@unix.bbn.comhaddock@ti-csl (05/09/86)
First a little tidbit: TI's 32K expansion memory is split into
two sections; one is 8K and goes in the low memory space and the
remaining 24K goes into what's left of the remaining 64k space.
Note that the 16K that's in the base machine belongs to the VDP
chips (9918a or just 9918 for the old 99/4).
As to 32K homebrew expansions: I've seen a coupla but that's been
many many moons ago. Try checking the ol' "99'er" Magazine,
currently called "Home Computing(?)". Check the ads in this one.
Also, Triton, Inc., based in San Francisco (I think) sells expansion
hardware from a number of suppliers. This was the company that took
over the TI software and remaining hardware when TI got out of the
home confuser :-) business.
Good luck,
-Rusty-
================================================================
*hardcopy* *electr{onic, ic}*
Rusty Haddock ARPA: Haddock%TI-CSL@CSNET-RELAY.ARPA
POB 226015 M/S 238 CSNET: Haddock@TI-CSL
Texas Instruments Inc. USENET: {ut-sally,convex!smu,texsun}!ti-csl!haddock
Dallas, Texas 75266 VOICE: (214) 995-0330