Motorola PowerQUICC II MPC8280 Series Reference Manual page 1320

Ethernet Command Set
Command
When used with the Ethernet controller, this command violates a specific behavior of an Ethernet/IEEE
STOP
802.3 station. It should not be used.
TRANSMIT
Used to smoothly stop transmission after the current frame finishes sending or undergoes a collision
GRACEFUL
(immediately if there is no frame being sent). FCCE[GRA] is set once transmission stops. Then the
STOP
Ethernet transmit parameters (including BDs) can be modified by the user. The TBPTR points to the
TRANSMIT
next TxBD in the table. Transmission begins when the R bit of the next BD is set and the
command is issued. Note that if the
TRANSMIT
current transmit frame ends in a collision, the TBPTR points to the beginning of the collided frame with
TxBD[R] still set (the frame looks as if it was never sent).
Enables transmission of characters on the transmit channel. It is expected by the Ethernet controller
RESTART
after a
TRANSMIT GRACEFUL STOP TRANSMIT
or late collision). The Ethernet controller resumes transmission from the current TBPTR in the channel
TxBD table.
Initializes all the transmit parameters in this serial channel parameter RAM to their reset state. This
INIT TX
command should be issued only when the transmitter is disabled. Note that the
PARAMETERS
PARAMETERS
Receive commands that apply to Ethernet are described in Table 36-4.
Command
After the hardware or software is reset and the channel in the FCC mode register is enabled, the
ENTER HUNT
channel is in the receive enable mode and uses the first BD in the table. This command is generally
MODE
used to force the Ethernet receiver to abort reception of the current frame and enter hunt mode. In hunt
mode, the Ethernet controller continually scans the input data stream for a transition of carrier sense
from inactive to active followed by a preamble sequence and the start frame delimiter. After receiving
the command, the current receive buffer is closed, the error status flags and length field are cleared,
RxBD[E] (the empty bit) is set, and the CRC calculation is reset. Further frame reception uses the
current RxBD.
Note that short frames pending in the internal FIFO may be lost.
Initializes all the receive parameters in this serial channel parameter RAM to their reset state and
INIT RX
should only be issued when the receiver is disabled. Note that the
PARAMETERS
can also be used to reset the receive and transmit parameters.
Used to set one of the 64 bits of the four individual/group address hash filter registers (GADDR[1–4] or
SET GROUP
IADDR[1–4]). The individual or group address (48 bits) to be added to the hash table should be written
ADDRESS
to TADDR_L, TADDR_M, and TADDR_H in the parameter RAM prior to executing this command. The
CP checks the I/G bit in the address stored in TADDR to determine whether to use the individual hash
table or the group hash table. A 0 in the I/G bit indicates an individual address; 1 indicates a group
address. This command can be executed at any time, regardless of whether the Ethernet channel is
enabled.
If an address from the hash table must be deleted, the Ethernet channel must be disabled,
the hash table registers must be cleared, and the
executed for the remaining preferred addresses. This is required because the hash table
might have mapped multiple addresses to the same hash table bit.
36-14
Freescale Semiconductor, Inc.
Table 36-3. Transmit Commands
command or transmitter error (underrun, retransmission limit reached,
command can also be used to reset the transmit and receive parameters.
Table 36-4. Receive Commands
MPC8280 PowerQUICC II Family Reference Manual
For More Information On This Product,
Go to: www.freescale.com
Description
command is issued and the
GRACEFUL STOP TRANSMIT
Description
INIT TX AND RX PARAMETERS
SET GROUP ADDRESS
RESTART
INIT TX AND RX
command
command must be
MOTOROLA