Motorola PowerQUICC II MPC8280 Series Reference Manual page 910

Common SMC Settings and Configurations
The SMC does not have to be fully disabled for parameter
RAM to be modified. Table 28-2 describes when parameter
RAM values can be modified. To disable all SCCs, SMCs, the
SPI, and the I
command.
28.2.4.1 SMC Transmitter Full Sequence
Follow these steps to fully enable or disable the SMC transmitter:
1. If the SMC is sending data, issue a
smoothly. If the SMC is not sending, if TBPTR is overwritten, or if an
command is executed, this command is not required.
PARAMETERS
2. Clear SMCMR[TEN] to disable the SMC transmitter and put it in reset state.
3. Update SMC transmit parameters, including the parameter RAM. To switch
protocols or reinitialize parameters, issue an
4. Issue a
RESTART TRANSMIT
5. Set SMCMR[TEN]. Transmission now begins using the TxBD that the TBPTR
value pointed to as soon as the R bit is set in the TxBD.
28.2.4.2 SMC Transmitter Shortcut Sequence
This shorter sequence reinitializes transmit parameters to the state they had after reset.
1. Clear SMCMR[TEN].
2. Issue an
INIT TX PARAMETERS
3. Set SMCMR[TEN].
28.2.4.3 SMC Receiver Full Sequence
Follow these steps to fully enable or disable the receiver:
1. Clear SMCMR[REN]. Reception is aborted immediately, which disables the SMC
receiver and puts it in a reset state.
2. Modify SMC receive parameters, including parameter RAM. To switch protocols
or reinitialize SMC receive parameters, issue an
3. Issue a
CLOSE RXBD
4. Set SMCMR[REN]. Reception immediately uses the RxBD that RBPTR pointed to
if E is set in the RxBD.
28-10
Freescale Semiconductor, Inc.
NOTE
2
C, use the CPCR to reset the CPM with a single
STOP TRANSMIT
if an
INIT TX PARAMETERS
command and make any additional changes.
command if
INIT RX PARAMETERS
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command to stop transmission
INIT TX PARAMETERS
was issued in step 3.
INIT RX PARAMETERS
was not issued in step 2.
INIT TX
command.
command.
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