Foundation's Edge By Travis Watford Several years ago, Foundation produced the first ram disk for the TI. When my TI memory card failed I convinced myself to shell out the bucks for their new card. Two hundred and seventy dollars bought me the Foundation 128k card with the DSR option. The ram disk had serious drawbacks; it allowed a maximum of three files and could not be accessed with any of the available disk managers. On the other hand, it was fast and it was the only ram disk available for the TI. I was satisfied; at least until other ram disks boasting greater capacity and complete floppy compatibility hit the market. As much as I wanted one of the newer cards, I could not justify replacing a working, if inferior, memory card. That's how the situation remained for years. Recently, however, I started exploring the possibility of upgrading my present card and found that it could be done. This article is the product of that work. While I can accept no responsibility for your results(let's be real, I'm just an individual), the steps outlined below have worked for me. The procedure is fairly simple and if you follow my instructions carefully, you should not have any problems. While I have painstakingly reviewed these instructions and feel certain that there are no mistakes, I won't be held liable for any misprints, be they my fault or not. Read these instructions carefully, paying particular attention to my descriptions of the card. If there are any discrepancies, DO NOT PROCEED. I assume that Foundation made no changes in the "REV 1" card, but if a trace or a chip is not where I say it is, STOP. Provided I haven't talked you out of it, $50-$60 and an evenings work from now you will have a ram disk second to none. Even if you have no intention of altering your card, I can offer some hope. To control the added capacity of the modified card, I am developing a new eprom based ram disk emulator. If you have the original software, I don't need to dwell on its shortcomings, you know them. Even the QS-Ramdisk software addresses few of the problems. While it will allow 127 files, you must load the software each time you power-up and still can't use your ram disk with disk managers. My operating system is designed to work with all popular disk managers, and being eprom based, is always present. This operating system can be used with unmodified Foundation cards as well as those altered as per this article. The software can be purchased(when complete) directly from me for $20. It will also be available, at no cost, in the form of a DF128 file, for those who have access to a eprom programmer. This software allows you, from console basic, to select the drive number(1-9) that the ram disk will respond to. The upgrade is in three independent parts, which can be done in any combination depending upon the level of compatibility desired. Fully upgraded, your Foundation card, as an alternative to my software, will run the Myarc eprom used in the Myarc 512k card, giving the Foundation all of the features boasted by the Myarc card; including Myarc Extended Basic. The Myarc software can be purchased(hopefully) directly from Myarc. Before we begin, some basic orientation: This article is written for Foundation 128k cards marked "REV 1"; The following terms will be used when describing the Foundation card: TOP - the side of the card nearest the top when installed; BOTTOM - the side that plugs into the box; FRONT - the side nearest the front of the p-box when installed; BACK - the side nearest the back of the box when installed; The card has four rows of chips labeled "A", "B", "C", and "D", with "A" at the TOP of the board and "D" at the BOTTOM. Ignore the numbers printed on the board, we will number chips from FRONT to BACK including positions that are drilled for IC's but are vacant. Thus A-1, A-5, B-1, C-1, and D-8 are empty slots. The sixteen memory chips are found from A-6 to A-13 and B-6 to B-13. We will be adding integrated circuits to two of the empty slots as well as utilizing unused portions of some existing chips. It is important that you always count the pins on the chips relative to the component side of the board. Pin 1 is the FRONT, TOP pin on all of the chips except C-5 and C-6. Pins are counted from pin 1 toward the BOTTOM. At the bottom of the chip, go straight across and continue counting toward the TOP. On a fourteen pin chip, pin 1 is the TOP, FRONT pin while pin 14 is the TOP, BACK pin. On chip C-6, start with pin 1 and count toward the BACK. At the bottom of the chip, move across and continue counting toward the FRONT. I don't want to bore anyone but it is imperative that EVERYONE understand. We will be making connections to the following integrated circuits so make sure they are as follows: A-3=74LS08 A-4=74LS40 B-2=74LS74 B-5=74LS259 C-2=74LS08 C-6=TMS4500A D-1=74LS00 D-4=74LS244 C-5=2732 I highly recommend using a low wattage soldering iron. For the jumpers, use 30 gauge wire-wrap type wire. All materials called for in this article, with the exception of the new memory chips and the 74LS02, are available at Radio Shack stores. At the end of this article you will find a complete parts list with Radio Shack parts numbers. On to the modifications. PART 1 As you have undoubtably noticed, the led on the Foundation card is lit whenever the power is on. With very little effort, you can change this so that it is lit only during ram disk accesses. On the component side of the board, cut the trace to the TOP lead of the led at the point where it bends to go toward the BACK of the card. Solder a 2N2222A transistor into any three holes at C-1. Attach a jumper from the transistor's emitter to pin 14 at D-1. Attach a jumper from the collector to the TOP pin of the led. Attach a jumper from the base to pin 4 at B-5. That's it. The led will only light when the ramdisk is accessed. Optionally, you can replace the led with a high-intensity one and replace the resistor with a 100 ohm resistor. The color code would be brown, black, brown. PART 2 This is a more complicated than the above change, but not too bad. First, connect all of the pin 1's on the sixteen memory chips together. That's the most tedious part. Install a 14 pin socket at A-5. Jumper pin 14 at A-4 to pin 14 at A-5. Jumper pin 7 at A-4 to pin 7 at A-5. Jumper pin 7 at B-5 to pin 9 at A-3. Jumper pin 9 at B-5 to pin 6 at A-5. Jumper pin 3 at A-5 to pin 4 at A-5. Jumper pin 10 at A-3 to pin 11 at A-3. Jumper pin 2 at A-5 to pin 8 at A-3. Jumper pin 5 at A-5 to pin 10 at A-3. Jumper pin 6 at C-6 to pin 12 at A-3. Jumper pin 7 at C-6 to pin 13 at A-3. Jumper pin 1 at A-6 to pin 1 at A-5. Jumper pin 27 at C-5 to pin 28 at C-5. Plug an integrated circuit, 74LS02, into the empty socket. That's it for the memory expansion folks. At this point, the board should operate exactly like it did before. Remove the memory chips and replace them with sixteen new chips. They can be ordered from: MICROPROCESSORS UNLIMITED, INC. 24,000 S. Peoria Ave. Beggs, OkAmQ~421 (918)267-4961 The parts number is 41256(150ns). These parts can be ordered elsewhere but I have found this distributor to be extremely reliable. Extreme care should be used whenever handling 256k memory chips. Don't handle the chips until you install them. Place a sheet of tin foil on a table. Lay the board, component side up, on the foil and gently put the chips on the foil. Keep one hand on the foil and with the other, plug each chip carefully into the board. This simple precaution can prevent premature failure of the chips. Once you have replaced the memory chips you will have a half megabyte of ram disk space. To use it you will need my software. The Foundation card is mapped to CRU address >1E00 instead of the Myarc's >1000. This prevents the card from working with the Myarc controller and makes the ram disk unavailable if it is given the same number as an active floppy disk. The Myarc ram disk will "mask" a floppy with the same number. That is, if the ram disk is set up as drive one, extended basic will pull the load file from the ram disk instead of the floppy. Multi-Plan, TI Writer, the Editor/Assembler and much other software will do the same. The system starts looking for disk drives at CRU address >1000. Since the floppies are at >1100 and your Foundation card is at >1E00, the system won't find the ram disk if it is set to the same number as an active floppy. The answer to this problem is to change the ram disk base address. The ideal location is >1000, like the Myarc card, so.... PART 3 Install a 14 pin socket at B-1. Jumper pin 14 at B-1 to pin 14 at B-2. Jumper pin 7 at B-1 to pin 7 at B-2. Jumper pin 8 at B-1 to pin 13 at C-2. Jumper pin 9 at B-1 to pin 5 at D-4. Jumper pin 10 at B-1 to pin 12 at A-4. Jumper pin 11 at B-1 to pin 9 at D-4. Jumper pin 12 at B-1 to pin 4 at A-3. Jumper pin 13 at B-1 to pin 7 at D-4. Cut the trace to pin 4 at A-3. This trace can be cut between A-3 and A-4 on the component side of the board. There should be four thin traces there, cut the third from the TOP. Cut the trace to pin 13 at C-2 on the component side of the board. The lead can be seen coming directly off the thirteenth pin. Cut the trace to pin 12 at A-4 on the solder side of the board. The trace can be seen coming directly off the twelth pin. Install a 74LS04 in the empty socket at B-1. That's all folks. You now own a half meg ram card ready to run my controller eprom or Myarc's. Enjoy Low wattage needle-point soldering iron - 64-2051 $5.95 30 gauge wire-wrap wire - 278-502 2.39 74LS04 - 276-1802 .99 1/4 watt 100 ohm resistor(optional) - 271-1311 .39 14 pin DIP sockets(2-pack) - 276-1999 .89 High brightness led(optional) - 276-066A 1.19 2N2222A transistor - 276-2009 .79 ------------------------------------------------------------------------------ The above was published in the August 1987 newsletter of the Midlands 99'ers. Travis Watford can be reached via the Club's BBS at 803-754-4996 at 300/1200 baud, or care of the club at: Midlands 99'ers P.O. Box 7586 Columbia, S.C. 29202 Any users of Omega can also get the latest bug report on Omega at the above BBS or you can leave reports of bugs. Larry Harpring Midland 99'ers GEnie (L.HARPRING) DELPHI (LJHARPRING)