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Device Testing
To start the software type "CHIPTEST". If you are using COM2 type "CHIPTEST /2". After a few moments the main menu should appear.

Option 1 allows the creation of new device files, and option 3 allows the editing of the currently loaded file. I will describe these in detail later. For now choose option 2 (press "2"), to load an existing device file. The available files will be listed on the screen (in alphabetical order if you have DOS 5 or later); if there is more than one screen full you will be prompted to press any key to see the next part. Note that the files have only the device base number. For example, 7432 is also suitable for 74LS32, 74HCT32, 5432 etc. from any manufacturer. Similarly 4024 is also suitable for 14024, 74HCT4024 etc.

You will now be prompted to type in the name of a device. Type "7400" if you have one of these devices (or enter the name of another basic logic device that you have available). The file will load and the main menu will reappear. The description below assumes a 7400.

Choose option 4 ("Test Device Once (Slow)"). A picture of a 14-pin device will appear, with instructions about how to fit it into the socket. Here you will be told to place it at the bottom of the socket, and set the power switch to 14. Do as requested then press any key.

The device will be tested one step at a time, and the logic state of each pin is shown using red for high and green for low. The test step number and result of this step (Pass or Fail) is shown at the top of the screen. At the end of the test the overall result is shown - accompanied by a beep if it failed. Hopefully yours passed!

Press any key to get back to the main menu. Choose 5 ("Test Device Once (Fast)") and the device will be tested again somewhat quicker, and without the individual step results. Generally you would use option 4 for debugging test routines and option 5 for actual testing. Option 6 ("Test Device Continually Until Fail") and Option 7 ("Test Device Continually Until Pass") are self explanatory - the number of complete tests completed is shown at the top of the screen.

If you want to see how the unit handles a faulty device, link pins 1 and 2 with a screwdriver and test it again. This fault will be detected because the inputs will not go to the levels they are set to. The testing routine checks the logic levels on all input and clock pins to make sure they are at the level they were set to.

Creating a new device file
We will now go on to create a new device file. We will stick with our 7400 for now, since we know it works! If you don't know this device, dig out a data book or the Maplin catalogue so you can follow what we're doing. Choose option 1 from the main menu and you will be prompted for a device name. Since you already have a good 7400 file which you probably don't want to overwrite, type "TEST" or something similar. You will now be prompted to enter the number of pins, type "14".

A picture of a 14-pin device will now appear, with a question mark by pin 1. You will be prompted to enter a pin type for pin 1, from the seven options at the bottom of the screen. "Input" and "Output" are obvious, "+ve Clock" is a clock pin that is normally low but needs high clock pulses and "-ve Clock" is the opposite of this. "VCC" is the positive supply, "GND" is the negative supply and "Unused" is - well - unused!

Press "1" to make pin 1 an input (no need to press <Enter>). The word "Input" will appear by pin 1 and the question mark will move to pin 2. Since this is also an input press "1" again. Pin 3 is an output so press "2". To finish the pin details enter "1", "1", "2", "6", "2", "1", "1", "2", "1", "1", "5". If you've got all this right, press "Y" to continue, otherwise press "N" to have another go.

You will now see a screen with pin numbers at the top, and some column dividing lines. Don't worry, it's not as bad as it looks! If there were any clock pins these would be on the left, the inputs come next, followed by the outputs. Dividing lines appear between each group. On the extreme left is the step number.