View Single Post
Old 9th Apr 2019, 8:12 pm   #156
SiriusHardware
Dekatron
 
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 3,042
Default Re: MK14 schematic revisions

A quick test for the I/O section of the INS8154 IC just using the monitor - assuming the new / improved monitor is in use.

First,

Code:
Abort
0 8 2 3
Term
F F
Mem
You won't see the data digits change, but doing this writes FF to the port 'B' data direction register to define all of the port B pins as outputs.

Then,

Code:
Abort
0 8 2 1
Term
5 5
Mem
This time, you will see the data digits change. This writes the pattern 01010101 to the port pins 0-7 of port B. You should be able to verify this with a meter, scope or logic probe.

Finally,
Code:
Abort
0 8 2 1
Term
A A
Mem
Should write the pattern 10101010 to bits 0-7 of port B.

I chose port B for this because the port pins 0 through to 4 appear in a sensible order on the edge connector. The port A pins are all over the place.
SiriusHardware is online now   Reply With Quote