HP82198 HP-IL video interface jumpers

[asciacca]

On the inside of the Mountain Computer HP82198 HP-IL video interface there are three jumpers that can be inserted that are labeled E1, E3 and E4; none of which have links installed. Does anyone know the purpose of these jumpers.

thanks,

Alan

[Sylvain Cote]

Alan

They are showed in the circuit diagram at P37 of the Owner manual.

Jumper E1 is connected to the EA pin of the Intel 8039 MCU.
Jumper E3 is connected to the T0 pin of the Intel 8039 MCU.
Jumper E4 is connected to the T1 pin of the Intel 8039 MCU.

There are all debugging pins for the 8039 micro-controller.

Intel MCS-48 Information Page - pin outs, etc.
http://www.nyx.net/~lturner/mcs48_pin.html

Mountain Computer used the NEC variant : D8039HLC
You can find the data sheet here:
http://www.datasheet-pdf.com/datasheetdo...?id=770369

Sylvain

[asciacca]

The 8039's T0 and T1 pins are tested by the application software written for the 8039 and they are usually used to modify the behavior of the application program. Mountain Computer wrote the application software for this device. I am still wondering what effect they have on the video interface.