Motorola MPC8260 用户手册

MOTOROLA

Chapter 19.  Serial Communications Controllers (SCCs)  

19-27

4. If an 

INIT

 

TX

 

PARAMETERS

 command was not issued in step 3, issue a 

RESTART

 

TRANSMIT

 command.

5. Set GSMR_L[ENT]. Transmission begins using the TxBD pointed to by TBPTR, 

assuming the R bit is set.

The following steps reinitialize an SCC transmit parameters to the reset state:

1. Clear GSMR_L[ENT].

2. Make any modiÞcations then issue the 

INIT

 

TX

 

PARAMETERS

 command.

3. Set GSMR_L[ENT].

An SCC receiver can be reconÞgured by following these steps:

1. Clear GSMR_L[ENR]. The SCC receiver is now disabled and put in a reset state.

2. Modify SCC Rx parameters or parameter RAM. To switch protocols or restore Rx 

parameters to their initial state, issue an 

INIT

 

RX

 

PARAMETERS

 command.

3. If the 

INIT

 

RX

 

PARAMETERS

 command was not issued in step 2, issue an 

ENTER

 

HUNT

 

MODE

 command.

4. Set GSMR_L[ENR]. Reception begins using the RxBD pointed to by RBPTR, 

assuming the E bit is set.

To reinitialize the SCC receiver to the state it was in after reset, follow these steps:

1. Clear GSMR_L[ENR].

2. Make any modiÞcations then issue the 

INIT

 

RX

 

PARAMETERS

 command.

3. Set GSMR_L[ENR].

To switch an SCCÕs protocol without resetting the board or affecting other SCCs, follow
these steps:

1. Clear GSMR_L[ENT, ENR].

2. Make protocol changes in the GSMR and additional parameters then issue the 

INIT

 

TX

 and 

RX

 

PARAMETERS

 command to initialize both Tx and Rx parameters.

3. Set GSMR_L[ENT, ENR] to enable the SCC with the new protocol.

To save power when not in use, an SCC can be disabled by clearing GSMR_L[ENT, ENR].