The ONE instruction outputs the value "1", and stores the result to a register, counter, or location in memory. For the latter, the address pointer must be setup before the ALU writes to memory. While technically a logical operation (the "1" evaluates as "true"), this is also useful for producing a value.

4C8A - Store the result to the "A" register.
4C8B - Store the result to the "B" register.
4C8C - Store the result to the "C" general purpose register.
4C8F - Store the result to the "F" output high register.

4C80 - Store the result to memory, at the current active address.
4C81 - Store the result to address pointer 1.
4C82 - Store the result to address pointer 2.