| ??? 02/24/07 21:17 Read: times |
#133637 - That code is pretty much what I use Responding to: ???'s previous message |
Michael Karas said:
Your idea to implement a hardware solution for a 16 byte sized "program" to implement the programming algorithm in your microcontroller is a almost as much of a zany idea as the earlier 64 byte version. Ok, fine, if 99.999% of the world thinks I am nuts to do this, ok, I am, but let me tell you that I learn alot more hands-on. It may seem zany, but at least I don't have to depend on a working rom or a rom programmer in order to program another rom! Despite that this is still technically possible but not really particularly practical in the way that you have indicated that you wish to implement it. I decided to make changes after Andy (or whoever) brought up the idea of using diodes and decoders. In my evaluation I still think it takes far too many gates to give any credibility to a goal to implement this with discrete logic. After me trying to come up with a minimized solution, I am better off using a few 3 or 4 input gates connected to the outputs of decoders. The code seems to be based upon the fact that you could write into the EEPROM from address zero, byte by byte, with no other type of handshaking or timing constraint. The clock on the 8051 will run forever. What I have however is synchronization, because it is waiting until a port pin has entered both logic states before the input from port 1 is accepted and processed. It clearly also assumes that the DPTR register is initialized at reset to a consistet value. I also assume that too, because the intel documentation claims it. ...drew up a schematic that uses a brute force batch of MUXes I thought about using multiplexers, but I'm better off using decoders (74HCT138). You may see a PDF of the schematic here: CrazyROM2 Schematic File I downloaded the PDF, but I don't recognize the schematic. All I see is a block with a few lines out of it for every page, and the first page had lines with a bunch of inverters. My estimate in looking at these equations is that it would take maybe 15 to 18 logic chips of the 14 and 16-pin variety to implement these equations. In that case, I'm sticking with decoders. Good Luck. PLEASE do not take my wish for good luck or the posting of this thread to be any kind of a source of endorsment of this idea to implement a 13 byte 8051 program via 18 logic packages. It is still a CrazyROM idea. Michael Karas I managed to condense the logic down to 7 or 8 IC packages including the decoders. I will still work on it. |
