

>>>>>>>>  TEST6066


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TARGET
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This is 32 KB sized code to go into ROM U18 (which is 32 KB sized) on an IBM 5160 (IBM XT) motherboard.

If your IBM 5160 motherboard is a 64-256KB type, the TMM23256/MK37000/MK38000 ROM's can in most cases be replaced with 27C256 EPROM's,
but some brands of 27C256 may be unsuitable for the 64-256KB motherboard - see http://www.minuszerodegrees.net/5160/motherboard/5160_u18_u19_sockets.htm
     
If your IBM 5160 motherboard is a 256-640KB type, then you can use a 27C256 (or 27256) EPROM, or a Winbond W27E257.
      
For the IBM 5160, use EPROM's that are rated at 250 ns, or faster.
See http://www.minuszerodegrees.net/5160/motherboard/IBM%205160%20motherboard%20-%20ROM%20description%20from%20TR.png


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REQUIRED
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1. A way of putting TEST6066_32KB_SIZED.BIN into a suitable ROM/EPROM/EEPROM.

2. Logic analyser (and the knowledge of how to use it).


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WHAT DOES THE CODE DO ?
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In a loop, the code:
Step 1: Reads address 55555 hex  (5555:0005) (01010101010101010101 binary)
Step 2: Reads address AAAAA hex  (AAAA:000A) (10101010101010101010 binary)

55555 and AAAAA chosen because they will reveal if any adjacent bits are 'shorted'.

An example of adjacent bits is A0 and A1.
An example of adjacent bits is A1 and A2.
An example of adjacent bits is A2 and A3.


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WHAT YOU SHOULD OBSERVE IF USING A LOGIC ANALYSER
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Reference diagram at https://minuszerodegrees.net/5160/misc/5160_address_bus.jpg

Using a logic analyser:
1. On the address bus, verify that two of the addresses seen are 55555 and AAAAA, i.e. all adjacent bits are at different logic states.
2. On the external address bus, verify that two of the addresses seen are 55555 and AAAAA, i.e. all adjacent bits are at different logic states.


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WHAT YOU SHOULD OBSERVE IF USING AN OSCILLOSCOPE
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Reference diagram at https://minuszerodegrees.net/5160/misc/5160_address_bus.jpg

Using an oscilloscope:
Verify that adjacent bits are at different logic states.

E.g. When you see A4 at HIGH, A3 and A5 should be LOW.


