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MOTOROLA
MC68306 USER'S MANUAL
6-41
WAS
IRQx CAUSED
BY BEGINNING
OF A BREAK
?
CLEAR CHANGE-IN-
BREAK STATUS BIT
HAS
END-OF-BREAK
IRQx ARRIVED
YET
?
CLEAR CHANGE-IN-
BREAK STATUS BIT
REMOVE BREAK
CHARACTER FROM
RECEIVER FIFO
REPLACE RETURN
ADDRESS ON SYSTEM
STACK AND MONITOR
WARM START ADDRESS
RTE
SIRQR
N
Y
N
DOES
CHANNEL A
RECEIVER HAVE A
CHARACTER
?
SAVE IN
SYSTEM BUFFER
N
Y
ABRKI1
ABRKI
Y
INCH
RETURN
SIRQ
Figure 6-10. Serial Module Programming Flowchart (4 of 5)