Freescale Semiconductor MPC8260 - Manual (Page 805)

SCC Ethernet Mode
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
Freescale Semiconductor 25-21
Figure 25-10 shows an example of interrupts that can be generated in Ethernet protocol.
Figure 25-10. Ethernet Interrupt Events Example
Note that the SCC status register (SCCS) cannot be used with the Ethernet protocol. The current state of
the RENA and CLSN signals can be found in the parallel I/O ports.
14 TXB Tx buffer. Set when a buffer has been sent on the Ethernet channel.
15 RXB Rx buffer. Set when a buffer that was not a complete frame was received on the Ethernet channel.
Table 25-9. SCCE/SCCM Field Descriptions (continued)
Bits Name Description
RXB
Line Idle
Stored in Rx Buffer
RXD
RENA
Frame
Received in Ethernet
Time
Line Idle
TXD
TENA
Frame
Transmitted by Ethernet
CLSN
TXB, GRA TXB
Line Idle Line Idle
Stored in Tx Buffer
NOTES
:
Ethernet SCCE
Events
1. RXB event assumes receive buffers are 64 bytes each.
2. The RENA events, if required, must be programmed in the parallel I/O ports, not in the SCC itself.
3. The RxF interrupt may occur later than RENA due to receive FIFO latency.
NOTES:
Ethernet SCCE
Events
1. TXB events assume the frame required two transmit buffers.
2. The GRA event assumes a GRACEFUL STOP TRANSMIT command was issued during frame transmission.
P SFD DA SA CR
RXF
3. The TENA or CLSN events, if required, must be programmed in the parallel I/O ports, not in the SCC itself.
T/L D
P SFD DA SA CR T/L D
LEGEND:
P = Preamble, SFD = Start frame delimiter, DA and SA = Source/Destination address,
T/L = Type/Length, D = Data, CR = CRC bytes