The engrammer operates by continuously counting through the entire 2048 byte NVRAM address space. By actuating the input DIP switches, certain address lines can be held continuously high or low, thus causing only a subset of the locations to be addressed. Normally, when the "Write" pushbutton is pressed, the previously engrammed output of the NVRAM will be re-written back into the chip on each cycle. However, by actuating some of the output DIP switches, certain bits can be tied always high or always low. This partially altered pattern is then written to chip to change the stored response patterns. The re-write mode can be disabled by the "Peek/Poke" toggle switch to instead allow viewing of the current contents of the NVRAM.

Block Diagram

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