ModSlaveSim help v3.07 - 4.4.2. On button and Off button - a simple latch
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A latch retains its value until it is told to change it.
This is achieved in the ModSlaveSim language by using an
if then without an else.
The simplest form of latch has an Output that can be 0 or 1, and two inputs: a Set input, which sets the output to 1, and a Reset input, which sets the Output to 0. If the Set and Reset inputs are both 0, the Output retains its last value.
It is similar to having two buttons - one for on and one for off. (Those with an electronics background will know this as a level-triggered RS flip-flop.)
Table 7. Simple latch
| Register Address | Register Name | Statement |
|---|---|---|
| $100 | Set | |
| $101 | Reset | |
| $102 | Output | if $100 != 0 then 1 else if $101 != 0 then 0 |