ZHCSKZ1 March 2020 SN74HCS20-Q1
PRODUCTION DATA.
In this application, two 4-input NAND gates are used to create an active-low SR latch as shown in Figure 9.
The SN74HCS20-Q1 is used to drive the tamper indicator LED and provide one bit of data to the system controller. When the tamper switch outputs LOW, the output Q becomes HIGH. This output remains HIGH until the system controller addresses the event and sends a LOW signal to the R input which returns the Q output back to LOW.