[ScottishColin]

First result 0

Second result 126.

Does that match what is supposed to happen?

Colin.

Originally Posted by SiriusHardware

Well, now that you are able to issue BASIC commands you can try these for a first-line check of the IEEE 488 port. This port is probably only important if you plan to acquire a disc drive or something which pretends it is one, such as the SD2PET.

Notice the POKE address is slightly different to the PEEK address in both cases.

POKE 59426,0
PRINT PEEK(59424)

Result=?

POKE 59426,255
PRINT PEEK(59424)

Result =?

The IEEE port has an unusually useful structure in so far as the state of the output latches can be read by the input buffers, so you can write a value to the 8 data bits of the IEEE port and read that value back, in the process proving both the output latches and the input buffers - provided the value you read back in is the same as the value you wrote out.