Working in Programming Mode (PGM)To enter Programming Mode, the operator presses the PGM button in the OPERATIONAL MODE block. Buttons in the PGM block illuminate to indicate that they can now be used (they are ignored in RUN and SLOW modes). The ADDRESS and DATA LEDs now show the address and content respectively from the default memory location; this has been set using an internal DIP switch.
Buttons EXAM- and EXAM+ can be used to navigate the memory from that point back and forward respectively. For each time, a memory read cycle is performed for updating the LEDs reading. If a different address is needed, this can be entered using the ENTRY switches, then pressing the ADDR button. The ADDRESS and DATA LEDs will then show the new address and content respectively.
To modify memory content, the operator enters the desired value using the ENTRY switches, then he presses the DTA button; this causes the new content to be written to memory and the address to be automatically incremented. This implies that, upon DTA button pressed, the address and data shown in the LEDs correspond, not to that just modified but to the one immediately next.
If, for instance, the operator wants to fill a block of memory with a given fixed data value, he needs to proceed as following:
1.- Enter the desired base address in the ENTRY switches.
2.- Press the ADDR button. Both address and memory content will be displayed.
3.- Enter the desired data in the ENTRY switches.
4.- Press the DTA button. Address and content for the next memory location will be displayed.
5.- Press the DTA button repeatedly as many times as needed. For each time, the current location will be written from the switches and the address will be incremented automatically.
A more practical example is to enter a "loader" program that allows the computer to load an existing application from storage.
Once the memory has been modified as desired, the operator enters the initial program address in the ENTRY swithes, presses the ADDR button and then presses the RUN button to star running the program. It can also chose to run the program in SLOW or STEP modes.
The computer can be halt at any time by pressing the HALT button in the OPERATIONAL MODE block.
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