Below a simple tester module is depicted. It is designed to facilitate the testing of other modules.
It has one incoming databus of 16 bit width. Each of the lower eight Leds of the two ten segment Led bars corresponds to one bit in the databus. The upper two Leds of the led display on the left hand side, are as follows:
- The uppermost Led should be on, whenever the most significant bit of the left outcoming databus is connected to the ground.
- The Led below is on to denote that the least significant bit of the same outcoming databus is connected to the power supply.
The two uppermost bits of the Led bar on the right hand side indicates whether we are in clock phase 1 or 2.
The content of the outcoming databus on the left hand side can be manipulated with the two red DIP switches. This bus may also be used to provide power supply to other modules linked to the tester. In such case, the switches designated with the plus and minus signs should be set to their respective position. Recall, this can be checked by looking at the status Leds of the left hand side Led bar.
The data on the other bus on the right hand side can also be given with the 2 Dip switches (one blue and one red). There are however, two special bits on this bus. Bit 10 and 16 represents Clock 1 and Clock 2 respectively. All the other bits can be used and set arbitrary.
The red button next to the 74Hc14 Schmitt trigger is used to move from clock phase 1 (i.e. Clock 1) to clock phase 2 (i.e. Clock 2).
I hope that with this very simple module I will be able to test - among others - the register module, which is planned to be implemented next.