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MOTOROLA
MC68306 USER'S MANUAL
6-39
N
Y
CHCHK
PLACE CHANNEL IN
LOCAL LOOPBACK
MODE
ENABLE CHANNEL'S
TRANSMITTER
CLEAR CHANNEL
STATUS WORD
IS
TRANSMITTER
READY
?
WAITED
TOO LONG
?
WAITED
TOO LONG
?
N
Y
SEND CHARACTER
TO TRANSMITTER
HAS
RECEIVER
RECEIVED
CHARACTER
?
CHCHK
TxCHK
SNDCHR
RxCHK
N
Y
N
SET TRANSMITTER-
NEVER-READY FLAG
SET RECEIVER-
NEVER-READY FLAG
A
B
Y
Figure 6-10. Serial Module Programming Flowchart (2 of 5)