

>>>>>>>>  TEST5000


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TARGET
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This is code to go into ROM U33 on an IBM 5150 (IBM PC) motherboard.
The IBM 5150 has special ROM requirements. See http://www.minuszerodegrees.net/5150/motherboard/5150_u33.htm


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REQUIRED
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1. A parallel (LPT) port POST code reader.
   See http://www.minuszerodegrees.net/images4/Parallel%20port%20monitoring%20POST%20board.jpg

2. A parallel (LPT) port on your computer that is at one of the following I/O addresses: 378 or 278 or 3BC

3. A way of putting the BIN file into a suitable ROM/EPROM/EEPROM.
   The IBM 5150 has special ROM requirements. See http://www.minuszerodegrees.net/5150/motherboard/5150_u33.htm


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BIN FILES
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Per http://www.minuszerodegrees.net/5150/motherboard/5150_u33.htm, if a suitable adapter is used, 16 KB and 32 KB sized ROM/EPROM's can be used on the IBM 5150 motherboard.
Because of that, included here are 16 KB and 32 KB versions of TEST5000_8KB_SIZED.BIN, being TEST5000_16KB_SIZED.BIN and TEST5000_32KB_SIZED.BIN

TEST5000_8KB_SIZED.BIN is for an MCM68766 EPROM, or a 2564 EPROM.
TEST5000_16KB_SIZED.BIN is for a 27C128 EPROM (in a suitable adapter).
TEST5000_32KB_SIZED.BIN is for a 27C256 EPROM (in a suitable adapter) or W27E257 EEPROM (in a suitable adapter).

Again, see http://www.minuszerodegrees.net/5150/motherboard/5150_u33.htm


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WHAT DOES THE CODE DO ?
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All that the code does is send the 4 bytes of {00}{FF}{55}{AA}, in that order, to LPT ports 378, 278, and 3BC, then it halts the CPU.

(There is a small delay between the 4 bytes, otherwise, as I discovered, the parallel port code reader misses bytes.)


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WHAT YOU SHOULD OBSERVE
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The last (repeat: last) 4 codes/bytes seen on your parallel port code reader should be {00}{FF}{55}{AA}, in that order.


If you are using the aforementioned reader:

1. [55][AA] will be the final display shown.

2. You then use the NEXT button as many times as required to see a history of the bytes received (received after power on of the reader).
   Example follows:
   [00][65]  <---- First byte received was 65 hex. Noise? Ignore it.
   [01][FF]  <---- Second byte received was FF hex. Noise? Ignore it.
   [02][E3]  <---- Third byte received was E3 hex. Noise? Ignore it.
   [03][44]  <---- Fourth byte received was 44 hex. Noise? Ignore it.
   [04][00]  <---- GOOD
   [05][FF]  <---- GOOD 
   [06][55]  <---- GOOD 
   [07][AA]  <---- GOOD 

   Above, I used the NEXT button to go back all the way to the first byte received.
   I did not need to do that.
   I really only needed to push the NEXT button four times, to see the LAST four bytes received.



