TI CC-40

Cameron Kaiser wrote: There is one really great source of technical information on the CC40 and its very close younger brother, the TI-74. Unfortunately, the scanned images are in a "Visioneer Paper Port" format. The free viewer is online at the same site, but it is too bad they aren't PDFs. I believe the following link is the right one, although it isn't responding right now. I hope it is just temporarily down and not gone. ftp://209.172.89.40/Hexbus_CC40_TI74/ If it is away for good, I sucked down a lot of the files anyway, so if you want hard-core info on the hexbus (and the closely related "dock bus" on the TI-74), I can set it along to you. It is a nicely designed bus (for its purpose, given the technology of the time). The basic idea is this: a 4b data bus with two handshake signals. All wires are driven open drain -- it is a true bus, not a point-to-point repeater arrangement. It is an async bus, and different peripherals can talk at differents speeds. The protocol is such that the transfer speed is determined by the slower party in the transaction. Say there are two high speed members and one slow one. The protocol speed will be slow if the source or target is the slow device, but in the case of fast->fast, the protocol is slow only until the point that the slow one realizes it isn't being addressed, then the speed picks back up again. There are some constraints on minimum and maximum handshake transitions (on the order of 8 microseconds minimum, a few milliseconds maximum), so it could easily all be managed in software. The TI calculators are a combination of dedicated bus controller and software interface. The processor the CC40 and TI-74 (and 95) use is an interesting one; quite different than many other 8b micros. Here is a link to a PDF describing the whole family of chips. The PDF is quite massive, and most of it goes into detail on configuring the myriad on-chip peripherals that exist on various members of the family. Go to section 16, which starts on page 485, to get to the instruction set. http://www-s.ti.com/sc/psheets/spnu127a/spnu127a.pdf Here are some other links, in no particular order. Some are much more informative than others. http://pw1.netcom.com/~bcostin/cc_ticc40.htm http://www.99er.net/cc40.html http://people.delphi.com/eicher/index.html http://people.delphi.com/eicher/CC40C.BIN (although it says .BIN, it is a text file, and quite informative) http://www.hightechsolutions.com/ti7495.htm http://www.zock.com/8-Bit/D_CC40.HTML http://www.rskey.org/cc40.htm http://home.debitel.net/user/groener1/comp_011.htm#CC-40 http://home.debitel.net/user/groener1/comp_011.htm#TI 74 http://members.aol.com/swim4home/cc40.html http://www.heimcomputer.de/comp/tizubehoer.html http://www.computingmuseum.com/museum/tipc.htm http://www.99er.net/ti74art.html http://home.inforamp.net/~crown/TI/ti.html#TI 74 BASICALC http://192.132.34.17/pub/electronics/microprocs/TMS7000/assemblers/ Finally, here is another uP based on a lot of the same technology as the CC40 and the TI-74: http://www.computingmuseum.com/museum/exl100.htm If you have any other good URL's you've found, please pass them on. ----- Jim Battle == frustum(a)pacbell.net