The RS latch has basically the same functions as an SR latch, except in the Forbidden state where both S and R equal ‘1’. In this state, an SR latch output will become ‘1’, but on the RS the output will be ‘0’.
The S-input is driven by the even LUT output (LUT0), and the R-input is driven by the odd LUT output (LUT1).
Figure 1. RS Latch
| S | R | OUT |
|---|---|---|
| 0 | 0 | Hold state (no change) |
| 0 | 1 | Clear |
| 1 | 0 | Set |
| 1 | 1 | Forbidden |