Motorola MPC8260 User Manual

28-20

MOTOROLA

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.

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].

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.