Motorola PowerQUICC II MPC8280 Series Reference Manual page 911

28.2.4.4 SMC Receiver Shortcut Sequence
This shorter sequence reinitializes receive parameters to their state after reset.
1. Clear SMCMR[REN].
2. Issue an
INIT RX PARAMETERS
3. Set SMCMR[REN].
28.2.4.5 Switching Protocols
To switch the protocol that the SMC is executing without resetting the board or affecting
any other SMC, use one command and follow these steps:
1. Clear SMCMR[REN] and SMCMR[TEN].
2. Issue an
INIT TX AND RX PARAMETERS COMMAND
parameters. Make any additional SMCMR changes.
3. Set SMCMR[REN, TEN]. The SMC is now enabled with the new protocol.
28.2.5 Saving Power
When SMCMR[TEN, REN] are cleared, the SMC consumes little power.
28.2.6 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[TXB] is set. Extract data from the RxBD if
SMCE[RXB] is set. To send another buffer, set TxBD[R].
3. Execute the rfi instruction.
28.3 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
MOTOROLA
Freescale Semiconductor, Inc.
command and make any additional changes.
Chapter 28. Serial Management Controllers (SMCs)
For More Information On This Product,
Go to: www.freescale.com
SMC in UART Mode
to initialize transmit and receive
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