SCC Ethernet Mode
MPC885 PowerQUICC Family Reference Manual, Rev. 2
27-18
Freescale Semiconductor
Figure 27-7
shows an example of how RxBDs are used in receiving.
Figure 27-7. Ethernet Receiving Using RxBDs
Buffer
0
0x0040
32-Bit Buffer Pointer
1
E
F
Receive BD 0
Status
Length
Pointer
0
0x0045
32-Bit Buffer Pointer
0
E
F
Receive BD 1
Status
Length
Pointer
1
XXXX
32-Bit Buffer Pointer
E
Receive BD 2
Status
Length
Pointer
1
XXXX
32-Bit Buffer Pointer
E
Receive BD 3
Status
Length
Pointer
Destination Address (6)
Source Address (6)
Type/Length (2)
Buffer
CRC Bytes (4)
Tag Byte (1)
Buffer
Buffer
Old Data from
Empty
64 Bytes
64 Bytes
64 Bytes
64 Bytes
Two Frames
Received in ethernet
Collision
Line Idle
Present
Time
Time
Buffer Full
Buffer Closed
after CRC Received.
Buffer
Still Empty
Empty
MRBLR = 64 Bytes for the SCC
Empty
Data Bytes (50)
Optional Tag Byte
Collision
Causes Buffer
to be Reused
0
L
1
L
Frame 2
Collided Frame will
be Overwritten
Appended
Non-Collided ethernet Frame 1
Summary of Contents for PowerQUICC MPC870
Page 98: ...MPC885 PowerQUICC Family Reference Manual Rev 2 I 4 Freescale Semiconductor ...
Page 118: ...MPC885 Overview MPC885 PowerQUICC Family Reference Manual Rev 2 1 20 Freescale Semiconductor ...
Page 158: ...The MPC8xx Core MPC885 PowerQUICC Family Reference Manual Rev 2 3 18 Freescale Semiconductor ...
Page 288: ...MPC885 PowerQUICC Family Reference Manual Rev 2 III 4 Freescale Semiconductor ...
Page 554: ...MPC885 PowerQUICC Family Reference Manual Rev 2 V 6 Freescale Semiconductor ...
Page 1090: ...UTOPIA Interface MPC885 PowerQUICC Family Reference Manual Rev 2 43 8 Freescale Semiconductor ...
Page 1312: ...Byte Ordering MPC885 PowerQUICC Family Reference Manual Rev 2 A 8 Freescale Semiconductor ...
Page 1336: ...MPC885 PowerQUICC Family Reference Manual Rev 2 D 16 Freescale Semiconductor ...
Page 1358: ...MPC885 PowerQUICC Family Reference Manual Rev 2 D 38 Freescale Semiconductor ...
Page 1370: ...MPC880 MPC885 PowerQUICC Family Reference Manual Rev 2 E 4 Freescale Semiconductor ...
Page 1386: ...Revision History MPC885 PowerQUICC Family Reference Manual Rev 2 I 2 Freescale Semiconductor ...