Motorola MPC860 PowerQUICC User Manual page 798

Part V. The Communications Processor Module
on-the-ßy changes are allowed, the sequences need not be followed and the register or bits
may be changed directly.
Note that the SMC does not have to be fully disabled for parameter RAM to be modiÞed.
Table 30-2 describes when parameter RAM values can be modiÞed. To disable the SCCs,
SMCs, SPI, and the I
30.2.4.1 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, this command is not required.
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 points to as soon as the R bit is set in that TxBD.
30.2.4.2 SMC Transmitter Shortcut Sequence
This shorter sequence reinitializes transmit parameters to the state they had after reset.
1. Clear SMCMR[TEN].
2. Make any changes, then issue an
3. Set SMCMR[TEN].
30.2.4.3 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 points to
if E is set in that RxBD.
30.2.4.4 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].
30-8
2
C, use CPCR[RST] to reset the CPM.
if an
INIT TX PARAMETERS
INIT TX PARAMETERS
command if
INIT RX PARAMETERS
INIT RX PARAMETERS
MPC860 PowerQUICC UserÕs Manual
command to stop transmission
STOP TRANSMIT
INIT TX PARAMETERS
was not issued in step 3.
command.
INIT RX PARAMETERS
was not issued in step 2.
command.
command.
command.
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