Motorola PowerQUICC II MPC8280 Series Reference Manual page 1012

Disabling the FCCs On-the-Fly
30.12.1 FCC Transmitter Full Sequence
For the FCC transmitter, the full disable and enable sequence is as follows.
1. Issue the
STOP TRANSMIT
transmitting data because it stops transmission in an orderly way. If the FCC is not
transmitting (no TxBDs are ready or the
been issued and completed), then the
Furthermore, if the TBPTR is overwritten by the user or the
command is executed, this command is not required.
2. Clear GFMR[ENT]. This disables the FCC transmitter and puts it in a reset state.
3. Make changes. The user can modify FCC transmit parameters, including the
parameter RAM. To switch protocols or restore the FCC transmit parameters to
their initial state, the
4. If an
INIT TX PARAMETERS
command.
TRANSMIT
5. Set GFMR[ENT]. Transmission begins using the TxBD that the TBPTR points to
as soon as TxBD[R] = 1.
30.12.2 FCC Transmitter Shortcut Sequence
A shorter sequence is possible if the user prefers to reinitialize the transmit parameters to
the state they had after reset. This sequence is as follows:
1. Clear GFMR[ENT].
2. Issue the
INIT TX PARAMETERS
now.
3. Set GFMR[ENT].
30.12.3 FCC Receiver Full Sequence
The full disable and enable sequence for the receiver is as follows:
1. Clear GFMR[ENR]. Reception is aborted immediately, which disables the receiver
of the FCC and puts it in a reset state.
2. Make changes. The user can modify the FCC receive parameters, including the
parameter RAM. If the user prefers to switch protocols or restore the FCC receive
parameters to their initial state, the
3. Issue the
ENTER HUNT MODE
command was not issued in step 2.
PARAMETERS
4. Set GFMR[ENR]. Reception begins immediately using the RxBD that the RBPTR
points to if RxBD[E] = 1.
30-22
Freescale Semiconductor, Inc.
command. This is recommended if the FCC is currently
INIT TX PARAMETERS
command was not issued in step 3, issue a
command. Any additional changes can be made
INIT RX PARAMETERS
command. This command is required if the
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GRACEFUL STOP TRANSMIT
command is not required.
STOP TRANSMIT
command must be issued.
command must be issued.
command has
INIT TX PARAMETERS
RESTART
INIT RX
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