Programmable Metastability Removing One Shot Pulse
Original Publication Date: 1988-Dec-01
Included in the Prior Art Database: 2005-Feb-15
Metastability is the state where an asynchronous signal to the data port of a latch is changing (not at a defined '0' or '1' logic level and the set clock C1 is going away (Fig. 1). The output of a latch in metastability can exhibit undesirable characteristics which vary, depending on the technology. It is desirable to prevent any other logic from seeing the output of a metastable latch until the latch comes out of metastability. Metastability can be controlled by allowing sufficient time for the latch to settle out of metastability. Programmability allows the circuit to remove metastability as quickly as possible, but also allows the flexibility to increase the time to remove metastability if a problem arises. The circuit in Fig. 2 generates clock gating signals used by the circuit in Fig.