Freescale Semiconductor PowerQUICC MPC885 Reference Manual page 803

29.2.4.4 SMC Receiver Shortcut Sequence
This shorter sequence reinitializes receive parameters to their state after reset.
1. Clear SMCMR[REN].
2. Make any changes, then issue an
3. Set SMCMR[REN].
29.2.4.5 Changing SMC Protocols
To switch the protocol that the SMC is executing without resetting the board or affecting the other SMC,
follow these steps:
1. Clear SMCMR[REN, TEN].
2. Make any SMCMR changes, modify the parameter RAM appropriately, and issue an
RX PARAMETERS COMMAND
3. Set SMCMR[REN, TEN]. The SMC is now enabled with the new protocol.
29.2.5 Saving Power
When the SMCMR[TEN, REN] are zero, the SMC consumes very little power.
29.2.6 Handling Interrupts in the SMC
Follow these steps to handle an interrupt in the SMC:
1. Once an interrupt occurs, read SMCE to identify the interrupt source. The SMCE bits are usually
cleared at this time.
2. Process the TxBD to reuse it if SMCE[TX] is set. Extract data from the RxBD if SMCE[RX] is set.
To send another buffer, set R in the TxBD.
3. Clear CISR[SMC1].
4. Execute the rfi instruction.
29.3 SMC in UART Mode
SMCs generally offer less functionality and performance in UART mode than do SCCs, which makes them
more suitable for simpler debug/monitor ports instead of full-featured UARTs. SMCs do not support the
following features in UART mode:
• RTS, CTS, and CD signals
• Receive and transmit sections clocked at different rates
• Fractional stop bits
• Built-in multidrop modes
• Freeze mode for implementing flow control
• Isochronous operation (1× clock) (That is, a 16× clock is required.)
• Interrupts on special control character reception
Freescale Semiconductor
INIT RX PARAMETERS
to initialize transmit and receive parameters.
MPC885 PowerQUICC Family Reference Manual, Rev. 2
Serial Management Controllers (SMCs)
command.
INIT TX AND
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