RS Latch

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
Table 1. RS Latch Behavior
S R OUT
0 0 Hold state (no change)
0 1 Clear
1 0 Set
1 1 Forbidden