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HIMEMV2 or equivillent PROM

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    #16
    I think we're on the same page. The "E2 JUMPER 1 to 2 ONLY" is what I had planned on using. On My motherboard e2 1-2 are connected by a soldered in wire that My Dad installed way back in the late '80s when we did the 640K mod.

    Comment


      #17
      Okay, if we use the first and third tables as described above, we can come up with a GAL16V8
      with a pin setup like this:

      Code:
                                  Chip diagram (DIP)
      
                                   ._____    _____.
                                   |     \__/     |
                                A6 |  1        20 | Vcc
                                A5 |  2        19 | A7
                                A4 |  3        18 | 
                                A3 |  4        17 | 
                                A0 |  5        16 | Q0
                                A1 |  6        15 | Q1
                                A2 |  7        14 | Q2
                                   |  8        13 | 
                                   |  9        12 |
                               gnd | 10        11 | 
                                   |______________|
      Note that Q3 isn't connected on the 5160 schematic and CE1, CE2 are always enabled. Rather than 4 tables, you get two, with duplicates.
      Reach me: vcfblackhole _at_ protonmail dot com.

      Comment


        #18
        Great!
        If I am interpretting your pin out correctly the only pin that will not line up directly is number 10. So I should be able to leave #8 disconnected and run a jumper from # 10 on the GAL to #8 on the motherboard socket. Do I need to do any thing with the other pins that are not used(#'s 13,17,18 )? Should they be left open or grounded?

        Comment


          #19
          Unlike regular CMOS, you can leave GAL pins open--the programming can essentially power off the circuitry associated with NC pins to save power. It really doesn't matter what you do with them. You can ground them if you like.

          I've run the simulation on the GAL and the output looks good.

          Unless you can program your own GALs and just need the JEDEC files, PM me with your address and I'll send you a programmed GAL to try out.
          Last edited by Chuck(G); November 29, 2011, 12:02 PM.
          Reach me: vcfblackhole _at_ protonmail dot com.

          Comment


            #20
            PM Sent. Thanks again Chuck(G)! I Can't wait to try it out! In my previous post I mentioned that I planned to leave pin 8 on the GAL disconnected and run a jumper form pin 10 to socket connector 8 gnd. However, based on your reply, I believe that I can leave pin 8 connected so that pin 8 and 10 would be connected to ground. That would be a little easier since to make pin 8 NC I would have to either cut it off the chip or modify the socket adapter so that pin 8 would be insulated. Sorry if I'm rambling on. So what do you think. Can pin 8 be grounded safely?

            Comment


              #21
              Sure, it's safe. On a 16V8, pins 1-9 and 11 are dedicated inputs. Pins 12-19 can be assigned as input or output. Any unassigned output is high-impedance, as are any unassigned inputs.

              GALs are usually named by their maximum numbers of inputs and outputs. So a 16V8 can have at most 16 inputs or 8 outputs, but obviously not both (you run out of pins). A 24-pin 22V10 can have up to 10 outputs or 22 inputs.
              Reach me: vcfblackhole _at_ protonmail dot com.

              Comment


                #22
                To anyone that might be following this thread, an update. Chuck say's that the GAL programmed to replicate the HIMEMV2 is on it's way to me by way of USPS. I'm so excited. I feel like a little kid waiting for Christmass. I have made the 16 to 20 pin adapter. Only took me two tries to get the solder job to look good. Good thing had some extra 20 pin low profile DIP sockets on hand. All that was required was soldering a jumper from pin 10 to pin 8, to provide ground, and trim the 4 extra pins down so that they won't interfere with the adjacent chip on th mother board.

                I'll give another update when I get it working.

                Have a Great Day

                Greg

                Comment


                  #23
                  It works! Checkit3 now finds(and tests as good) 128k of "Hi RAM" in the D000h to F000h region. Now, I just need to figure out how to make use of this chunk of ram. I've been un-able to find old versions of QEMM or QRAM. I'm not sure that either of these wold work without a LIM 4 Board but I was hoping... Any ideas?

                  Comment


                    #24
                    A couple of things occur to me.

                    You could simply insert the free memory in DOS's memory allocation tables and see if anyone uses it.

                    You could grab the source for a DOS RAMDisk or cache and hack it (if there's not such a product out there already) to use a user-specified block of memory.

                    I suspect that it would be simple to take a copy of the source to HIMEM.SYS and alter it to tell DOS that your 192K is simply your version of an HMA (i.e. load device drivers and TSRs up there).
                    Reach me: vcfblackhole _at_ protonmail dot com.

                    Comment


                      #25
                      Here are the GAL16V8 JEDEC, EQN and LOG files for anyone who wants to duplicate this. Since you'll be putting a 20-pin DIP iinto a 16-pin socket, you'll need to connect pins 8 and 10 (it's okay to include pin 9 if that makes the job easier) on the 20 pin DIP or, if you use a stacked socket, the socket. Just plug the GAL in so that pin 1 on the GAL matches pin 1 of U44 on the 5160 planar. Stick in 4 banks of 41256s and you're good to go.
                      Attached Files
                      Reach me: vcfblackhole _at_ protonmail dot com.

                      Comment


                        #26
                        Originally posted by Chuck(G) View Post
                        Here are the GAL16V8 JEDEC, EQN and LOG files for anyone who wants to duplicate this. Since you'll be putting a 20-pin DIP iinto a 16-pin socket, you'll need to connect pins 8 and 10 (it's okay to include pin 9 if that makes the job easier) on the 20 pin DIP or, if you use a stacked socket, the socket. Just plug the GAL in so that pin 1 on the GAL matches pin 1 of U44 on the 5160 planar. Stick in 4 banks of 41256s and you're good to go.
                        Also, I'd be willing to make the adapter socket. I still have three un modified low profile 20 pin sockets on hand. I like the low profile type because the pins are a little more substantilal than the full hieght type, and they have a shoulder that stays above the socket that it is plugged into which is were the jumper is installed.

                        I'd be willing to provide one free of charge, including shipping, to anyone willing to help with the software side. Just PM me.

                        Comment


                          #27
                          Originally posted by ibmapc View Post
                          It works! Checkit3 now finds(and tests as good) 128k of "Hi RAM" in the D000h to F000h region. Now, I just need to figure out how to make use of this chunk of ram. I've been un-able to find old versions of QEMM or QRAM. I'm not sure that either of these wold work without a LIM 4 Board but I was hoping... Any ideas?
                          This really is a great piece of work coming together here. Hats off to those involved.

                          As it happens I have a Tandy 1400FD outside which has 768K RAM from the factory, so I guess it used a similar trick (V20 CPU). I'd be very interested to get a copy of this Checkit3 utility you mention if possible.

                          I think on the 1400 the idea for the extra RAM was disk cache (especially since it was floppy based). But as yet I've not been able to find really anything about it at all (let alone a driver).

                          Comment


                            #28
                            I FOUND IT!!
                            After searching and scouring the internet as well as these forums, I found a handler that actually works on the XT. It's called "Use!UMBS". Awfull name, but it works. I now have 128k of UMB. I am able to load a lot of drivers and tsr's up there. With MS Network Client with Netbeui all loaded high along with a bunch of other stuff I have 576k of base memory available and there is still 11k of upper memory free!! If your interested, here's THE LINK. This is awsome. UMB on an XT without an expensive memory board!! Thanks again Chuck(G)!!

                            Later,

                            Greg

                            Comment


                              #29
                              Great to hear it's working!

                              Originally posted by pearce_jj View Post
                              I have a Tandy 1400FD outside which has 768K RAM from the factory, so I guess it used a similar trick (V20 CPU). I'd be very interested to get a copy of Checkit3
                              A bit off-topic, but checkIt didn't find the extra 128K in the 1400. I also found an original Tandy DOS disk for it, but alas can't see any drivers for it on there either!

                              Comment


                                #30
                                Originally posted by pearce_jj View Post
                                Great to hear it's working!



                                A bit off-topic, but checkIt didn't find the extra 128K in the 1400. I also found an original Tandy DOS disk for it, but alas can't see any drivers for it on there either!
                                I believe Checkit v 3.0 was the first one to have a memory map feature. Thats where I was able to see the "reserved" area which is the space between 640k and 1meg

                                PM sent

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