Datasheet

Section 17 Keyboard Buffer Controller
Rev. 4.00 Sep 27, 2006 page 573 of 1130
REJ09B0327-0400
17.3.3 Receive Abort
The H8S/2148 Group and H8S/2147N device (system side) can forcibly abort transmission from
the device connected to it (keyboard side) in the event of a protocol error, etc. In this case, the
system holds the clock low. During reception, the keyboard also outputs a clock for
synchronization, and the clock is monitored when the keyboard output clock is high. If the clock is
low at this time, the keyboard judges that there is an abort request from the system, and data
transmission from the keyboard is aborted. Thus the system can abort reception by holding the
clock low for a certain period. A sample receive abort processing flowchart is shown in figure
17.7, and the receive abort timing in figure 17.8.