User manual

Fast Communications Controllers (FCCs)
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
Freescale Semiconductor 29-21
29.12.1 FCC Transmitter Full Sequence
For the FCC transmitter, the full disable and enable sequence is as follows.
1. Issue the STOP TRANSMIT command. This is recommended if the FCC is currently transmitting data
because it stops transmission in an orderly way. If the FCC is not transmitting (no TxBDs are ready
or the GRACEFUL STOP TRANSMIT command has been issued and completed), then the STOP
TRANSMIT command is not required. Furthermore, if the TBPTR is overwritten by the user or the
INIT TX PARAMETERS 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 INIT TX
PARAMETERS command must be issued.
4. If an INIT TX PARAMETERS command was not issued in step 3, issue a RESTART TRANSMIT
command.
5. Set GFMR[ENT]. Transmission begins using the TxBD that the TBPTR points to as soon as
TxBD[R] = 1.
29.12.2 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 command. Any additional changes can be made now.
3. Set GFMR[ENT].
29.12.3 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
INIT RX PARAMETERS command must be issued.
3. Issue the
ENTER HUNT MODE command. This command is required if the INIT RX PARAMETERS
command was not issued in step 2.
4. Set GFMR[ENR]. Reception begins immediately using the RxBD that the RBPTR points to if
RxBD[E] = 1.
29.12.4 FCC Receiver Shortcut Sequence
A shorter sequence is possible if the user prefers to reinitialize the receive parameters to the state they had
after reset. This sequence is as follows:
1. Clear GFMR[ENR].