An apparatus for determining the validity of a data signal communicated between
two microprocessors by a dual port RAM includes a sender for providing a data signal
and an initialization status indicator and a dual port RAM in communication with
the sender for receiving the data signal and the initialization status indicator.
The RAM has a first location for storing the data signal and a second location
for storing the initialization status indicator. The sender performs initialization
on the RAM at the beginning of a data transfer cycle which includes a plurality
of data transfer from the sender to a receiver. The sender updates the initialization
status indicator as the initialization progresses. The receiver reads the initialization
status of the RAM from the second location and subsequently reads the data signal
from the first location in association with the initialization status of the RAM.
