Freescale Semiconductor MPC8260 - Manual (Page 777)

SCC Transparent Mode
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
Freescale Semiconductor 24-7
Table 24-4 describes receive commands.
24.8 Handling Errors in the Transparent Controller
The SCC reports message reception and transmission errors using the channel buffer descriptors, the error
counters, and SCCE.
Table 24-5 describes transmit errors.
Table 24-6 describes receive errors.
RESTART
TRANSMIT
Reenables transmission of characters on the transmit channel. The transparent controller expects
it after a
STOP TRANSMIT command is issued (at which point the channel is disabled in SCCM), after
a GRACEFUL STOP TRANSMIT command is issued, or after a transmitter error. The transparent
controller resumes transmission from the current TBPTR in the channel TxBD table.
INIT TX
PARAMETERS
Initializes all transmit parameters in the serial channel parameter RAM to reset state. Issue only
when the transmitter is disabled.
INIT TX AND RX PARAMETERS resets receive and transmit
parameters.
Table 24-4. Receive Commands
Command Description
ENTER HUNT
MODE
After hardware or software is reset and the channel is enabled, the channel is in receive enable
mode and uses the first BD in the table.
ENTER HUNT MODE forces the transparent receiver to the
current frame and enter hunt mode where the transparent controller waits for the synchronization
sequence. After receiving the command, the current buffer is closed. Further data reception uses
the next BD.
CLOSE RXBD Forces the SCC to close the RxBD if it is being used and to use the next BD for any subsequently
received data. If the SCC is not receiving data, no action is taken by this command.
INIT RX
PARAMETERS
Initializes all receive parameters in this serial channel parameter RAM to reset state. Issue only
when the receiver is disabled.
INIT TX AND RX PARAMETERS resets receive and transmit parameters.
Table 24-5. Transmit Errors
Error Description
Transmitter
Underrun When this occurs, the channel stops sending the buffer, closes it, sets TxBD[UN], and generates a
TXE interrupt if it is enabled. Transmission resumes after a
RESTART TRANSMIT command is received.
Underrun occurs after a transmit frame for which TxBD[L] was not set. In this case, only SCCE[TXE]
is set. Underrun cannot occur between transparent frames.
CTS Lost During
Message
Transmission When this occurs, the channel stops sending the buffer, closes it, sets TxBD[CT], and generates the
TXE interrupt if it is enabled. The channel resumes sending after
RESTART TRANSMIT is received.
Table 24-3. Transmit Commands (continued)
Command Description