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Serial Management Controllers (SMCs)
MC68360 USER’S MANUAL
data), data will begin to be transmitted on the next falling edge of SMCLK after one character
of ones is transmitted. If the transmit FIFO is loaded at some later time, the data will begin
transmission after some multiple number of all-ones characters is transmitted. The transmit-
ter will never lose synchronization again, regardless of the state of SMSYNx, until the TEN
bit is cleared by the user or the ENTER HUNT MODE command is issued.
If both the REN and TEN bits are set in SMCMR, the first falling edge of the SMSYNx pin
causes both the transmitter and receiver to achieve synchronization. To re-synchronize the
transmitter, the SMC transmitter may be disabled and reenabled, and the SMSYNx pin can
be used again to re-synchronize just the transmitter. See 7.11.5 Disabling the SMCs on the
Fly for a description of how to safely disable and reenable the SMC (simply clearing TEN
and setting TEN may not be sufficient). The receiver may be re-synchronized in a similar
fashion.
7.11.10.7 USING THE TSA FOR SYNCHRONIZATION. The TSA offers a method to syn-
chronize the SMC channel internally without using the SMSYNx pin. This behavior is similar
to that of the SMSYNx pin, except that the synchronization event is not the falling edge of
the SMSYNx pin, but rather the first time slot for this SMC receiver/transmitter following the
frame sync indication. See 7.8 Serial Interface with Time Slot Assigner for further informa-
tion on configuring time slots for the SMCs and SCCs.
The TSA allows the SMC receiver and transmitter to be enabled simultaneously, yet syn-
chronized separately, a capability not provided by the SMSYNx pin. See Figure 7-79 for an
example of synchronization using the TSA.
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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