This is revision A of the EMDP3 DIP48Z checker board and it is currently a work in progress.

EMDP3 DIP48Z Checker Board (Revision A)

Introduction

The DIP48Z check board is used to verify that a DIP48Z universal rewiring plug is properly wired. It accomplishes this by providing the ability to distinguish between 5 volts and ground on every pin of the 48-pin ZIF socket on the DIP48Z adaptor. There are six 74HC165 8-bit parallel load shift registers attached to the 48 pins of the ZIF socket with 10K pull-up resistors. The main unit loads the 165's and shifts out all of the pin values via the ID lines on the bus.

The basic algorithm is as follows:

1. All BD lines, VAR1, VAR2, and VIO are set to 5 volts. Any pins that read as 0 volts are assumed to correspond to pins connected to ground.
2. VAR1, VAR2, and VIO are each respectively set to 0 volts to determine which pins are connected to VAR1, VAR2, and VIO.
3. Each BD line is sequentially set to 0 volts to figure out which BD lines are attached to to which pins.
4. Any wiring errors are deduced and reported to the user.

Cirucuit Schematics

The DIP48Z adaptor has a 48-pin ZIF socket on it.