MSC8113 Reference Manual, Rev. 0
25-28
Freescale Semiconductor
Ethernet Controller
25.10 Buffer Descriptors
The Ethernet controller stores data in memory regions defined by buffer descriptors (BDs), which
are defined as transmit buffers (TxBDs) or receive buffers (RxBDs) that are organized and
accessed through BD tables. The Ethernet controller BDs have the following features:
Configurable BD size via ECNTRL[DBDS].
— 8-byte BDs are compatible with other Ethernet interfaces, such as the MSC8101,
MSC8103, MPC8260, and MPC8560 devices, permitting reusability of existing
Ethernet applications from these devices. Features include:
•
Pattern matching reject
•
Filing capability
— Extended BD mode attribute information includes:
•
Frame status
•
Extended address match results
•
Extended pattern match results
•
Insertion information on the transmitting side
•
Frame data length
•
Insertion with expansion or replacement
The 8-byte BD mode imposes some limitations primarily because of the lack of reporting means
(no more fields in the BD to report events). Even with this limitation, significant pattern
matching and filing is possible. However, insertions cannot be performed on the transmitting
side. Pattern matching can be used to define up to eight more station addresses. Pattern match
reject can also be performed in 8-byte mode.
Use the Default Attribute Register to change the default filing queue. These features can reduce
the memory space (smaller BD rings) required and increase performance (less DMA read/write
required for the 8-byte BD as compared to the 32-byte BD). Using the 32-byte BD, you can
customize the automatic insertion of information received and transmitted based on Ethernet
address, IP address, and so on, and
use this information for filtering, security, or other custom
applications. The RxBD contains a summary of the receive frame attributes; including pattern
match and address match. The TxBD can be used to modify the transmitted information by
inserting customized data.
25.10.1 Data Buffer Descriptor
Data BDs encapsulate all information necessary for the Ethernet controller to transmit or receive
an Ethernet frame (see Figure 25-19). The BD centralizes status information for the data packet
in its status field and contains a data BD pointer to the location of the data buffer. Software sets
up the BDs in memory. Because of prefetching, a minimum of two BDs per ring are required.
This applies to both the transmit and the receive descriptor rings. Software also points the data
Summary of Contents for MSC8113
Page 1: ...MSC8113 Reference Manual Tri Core 16 Bit Digital Signal Processor MSC8113RM Rev 0 May 2008 ...
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Page 56: ...MSC8113 Reference Manual Rev 0 1 28 Freescale Semiconductor MSC8113 Overview ...
Page 76: ...MSC8113 Reference Manual Rev 0 2 20 Freescale Semiconductor SC140 Core Overview ...
Page 134: ...MSC8113 Reference Manual Rev 0 4 30 Freescale Semiconductor System Interface Unit SIU ...
Page 168: ...MSC8113 Reference Manual Rev 0 6 18 Freescale Semiconductor Boot Program ...
Page 180: ...MSC8113 Reference Manual Rev 0 7 12 Freescale Semiconductor Clocks ...
Page 260: ...MSC8113 Reference Manual Rev 0 8 80 Freescale Semiconductor Memory Map ...
Page 300: ...MSC8113 Reference Manual Rev 0 9 40 Freescale Semiconductor Extended Core ...
Page 304: ...MSC8113 Reference Manual Rev 0 10 4 Freescale Semiconductor MQBus and M2 Memory ...
Page 308: ...MSC8113 Reference Manual Rev 0 11 4 Freescale Semiconductor SQBus ...
Page 590: ...MSC8113 Reference Manual Rev 0 17 46 Freescale Semiconductor Interrupt Processing ...
Page 614: ...MSC8113 Reference Manual Rev 0 18 24 Freescale Semiconductor Debugging ...
Page 622: ...MSC8113 Reference Manual Rev 0 19 8 Freescale Semiconductor Internal Peripheral Bus IPBus ...
Page 724: ...MSC8113 Reference Manual Rev 0 21 32 Freescale Semiconductor UART ...
Page 920: ...MSC8113 Reference Manual Rev 0 25 150 Freescale Semiconductor Ethernet Controller ...
Page 1171: ...MSC8113 Reference Manual Rev 0 Freescale Semiconductor C 61 EF wait_rts P 01077FFC 9F rts 71 ...
Page 1172: ...MSC8113 Reference Manual Rev 0 C 62 Freescale Semiconductor MSC8113 Boot Code ...
Page 1202: ...MSC8113 Reference Manual Rev 0 Index 30 Freescale Semiconductor Index ...