Motorola PowerQUICC II MPC8280 Series Reference Manual page 850

SCC Ethernet Event Register (SCCE)/Mask Register (SCCM)
Table 25-9. SCCE/SCCM Field Descriptions (continued)
Bits Name
9–10 — Reserved, should be cleared.
11 TXE Set when an error occurs on the transmitter channel. This event is not maskable via the TxBD[I] bit.
12 RXF Rx frame. Set when a complete frame has been received on the Ethernet channel.
13 BSY Busy condition. Set when a frame is received and discarded due to a lack of buffers.
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.
Figure 25-10 shows an example of interrupts that can be generated in Ethernet protocol.
Frame
Received in Ethernet
Time
RXD Line Idle
RENA
Ethernet SCCE
Events
NOTES
:
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.
Frame
Transmitted by Ethernet
TXD Line Idle
TENA
CLSN
Ethernet SCCE
Events
NOTES:
1. TXB events assume the frame required two transmit buffers.
2. The GRA event assumes a
3. The TENA or CLSN events, if required, must be programmed in the parallel I/O ports, not in the SCC itself.
LEGEND:
P = Preamble, SFD = Start frame delimiter, DA and SA = Source/Destination address,
T/L = Type/Length, D = Data, CR = CRC bytes
Figure 25-10. Ethernet Interrupt Events Example
25-22
Freescale Semiconductor, Inc.
Stored in Rx Buffer
P SFD DA SA T/L
Stored in Tx Buffer
P SFD DA SA T/L
TXB
command was issued during frame transmission.
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Description
D CR Line Idle
RXB RXF
D CR Line Idle
TXB, GRA
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