TI-H: TI-85 RAM

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TI-H: TI-85 RAM


Hi everybody!

    I've recently signed some TI lists (ones having anything to do with TI85). I hope none of them is dead... Well - here's my question: TI85 has 128kb ROM, right? How the hell it is possible with address lines A0-A15???? I am sure, that 16 address lines with 8-bit organization gives 64kb. Not a bit more. How's that? CPU seems to have 16 address lines, too.

    I know it uses banking, but at least ROM should have 17 address lines to have 128kb. Or perhaps the banking is done by ROM internally??? I haven't heard of such a memory, but nobody knows...

    Regarding the last discussion about sockets, I've installed in my TI85 an extra socket, under the ENTER key. It is a 10pin IDC sock (one ripped form PC COM port on MB - I do plenty of things from elements ripped from old PC equipment), with connects to power and link. The power is connected via diode switch (gee, I need Shottky low drop diodes;), so connecting external power supply won't blow batteries and external devices can't be run off internal batteries. Now I have integrated power/serial cable. And the socket (black silhouette) looks nearly as an original equipment. Thie only drawback is the spaghetti inside - it is really hard to close the cover due to cables inside ;(

    More to linking topics (hopefully, electrical side is all the same) - did anyone think about using I2C repeaters (Philips' P82B715) do extend link range? Philips claims they built 400m I2C connection using two P82B715 and a flat ribbon cable (every second wire grounded). Using some extra stuff (current pumps) they built a 1 mile (1828.8m) I2C connection. Seems impressive to me. See Philips' WWW page AN452 (1 mile conn.) and AN444 (400m connection) for details.

    You may use link to direct-connect TI calculators to I2C microcontrollers (eg. 80552, some PICs). If you hack CBL/CBR protocol, you may do lots of interesting stuff, including sophisticated data aquisition hardware.

    The last, but not the least - you may easily make solid state diskette (SSD) using:
        a. 87C552 - master control
        b. as much CMOS SRAM (battery backed up) as necessary,
        c. few keys and LCD display to select program to be sent back to TI

        d. optional - perhaps 1.44" disk drive????

    The system could work as active receiver - it listens to TI all the time. If TI sends data, it is immediately stored in SSD RAM. If user wants to retrieve program, selects it on LCD display and sets TI to hearing - it is loaded right back. Note - this is a 'legal' solution, I mean it needs no shells, managers or drivers.

    Keep developing,
        Best regards,
           Pawel Kraszewski - mailto:pkraszewski@BigFoot.COM
   /\                         http://www.bigfoot.com/~pkraszewski
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P.S. Is there *ANY* TI85 link program working fine (I mean fast) on NT?