Status indication detection device and method

摘要

A status indication detection apparatus (SIDM) comprises an input storage stage (INS), an intermediate storage stage (ISS) and an output storage stage (OSS). Status indications (IN_STATUS) are input into the input register (INM) of the input stage (INS) and are shifted to the intermediate and to the output stage (ISS; OSS). The input and intermediate storage stages operate with a first reference clock (CLK_A) in a first clock domain (A) whilst the output storage stage operates with a different second reference clock (CLK_B) in the second clock domain (B). In accordance with the invention a reading out of the intermediate register (INT) of the intermediate stage (ISS) is only possible during the generation of a hold signal (LOCK) which keeps a current status indication in the intermediate storage stage (ISS) and blocks a transfer of a new status indication from the input stage (INS). Since the hold signal (LOCK) duration covers at lest one second clock reference period, a read out pulse (STROBE) can be placed within the hold signal duration (LOCKL). Thus, even at different phase and /or frequency relationships between the first and second reference clock (CLK_A, CLK_B) a metastability in the output register (ORM) can be avoided and no status indications output from the hardware device (HW) get lost. <IMAGE>