參數(shù)資料
型號: 82559
廠商: INTEL CORP
元件分類: 微控制器/微處理器
英文描述: Fast Ethernet Multifunction PCI/CARD bus controller(快速以太網(wǎng)多功能PCI/CARD 總線控制器)
中文描述: 1 CHANNEL(S), 100M bps, LOCAL AREA NETWORK CONTROLLER, PBGA196
封裝: 15 X 15 MM, BGA-196
文件頁數(shù): 34/124頁
文件大?。?/td> 1332K
代理商: 82559
82559 — Networking Silicon
24
Datasheet
4.2.1.2.1
Memory Write and Invalidate
The 82559 has four Direct Memory Access (DMA) channels. Of these four channels, the Receive
DMA is used to deposit the large number of data bytes received from the link into system memory.
The Receive DMA uses both the Memory Write (MW) and the Memory Write and Invalidate
(MWI) commands. In order to use MWI, the 82559 must guarantee the following:
1. Minimum transfer of one cache line
2. Active byte enable bits (or BE#[3:0] are all low) during MWI access
3. The 82559 may cross the cache line boundary only if it intends to transfer the next cache line
too.
In order to ensure the above conditions, the 82559 may use the MWI command only if the
following conditions hold:
1. The Cache Line Size (CLS) written in the CLS register during PCI configuration is 8 or 16
Dwords.
2. The accessed address is cache line aligned.
3. The 82559 has at least 8 or 16 Dwords of data in its receive FIFO.
4. There are at least 8 or 16 Dwords of data space left in the system memory buffer.
5. The MWI Enable bit in the PCI Configuration Command register, bit 4, should is set to 1b.
6. The MWI Enable bit in the 82559 Configure command should is set to 1b. (Details on the
Configure command are described in the
10/100 Mbit Family Software Developer’s Manual
.)
If any one of the above conditions does not hold, the 82559 will use the MW command. If a MWI
cycle has started and one of the conditions is no longer valid (for example, the data space in the
memory buffer is now less than CLS), then the 82559 terminates the MWI cycle at the end of the
cache line. The next cycle will be either a MW or MWI cycle depending on the conditions listed
above.
If the 82559 started a MW cycle and reached a cache line boundary, it either continues or
terminates the cycle depending on the Terminate Write on Cache Line configuration bit of the
82559 Configure command (byte 3, bit 3). If this bit is set, the 82559 terminates the MW cycle and
attempts to start a new cycle. The new cycle is a MWI cycle if this bit is set and all of the above
listed conditions are met. If the bit is not set, the 82559 continues the MW cycle across the cache
line boundary if required. (Details on the Configure command are described in the
10/100 Mbit
Family Software Developer’s Manual
.)
4.2.1.2.2
Read Align
The Read Align feature enhances the 82559’s performance in cache line oriented systems. In these
particular systems, starting a PCI transaction on a non-cache line aligned address may cause low
performance.
In order to resolve this performance anomaly, the 82559 attempts to terminate transmit DMA
cycles on a cache line boundary and start the next transaction on a cache line aligned address. This
feature is enabled when the Read Align Enable bit is set in the 82559 Configure command (byte 3,
bit 2). (Details on the Configure command are described in the
10/100 Mbit Family Software
Developer’s Manual
.)
If this bit is set, the 82559 operates as follows:
相關(guān)PDF資料
PDF描述
8255A-5 PROGRAMMABLE PERIPHEAL INTERFACE
8255A IC LOGIC 3257 4-BIT 1-OF-2 FET MULTIPLEXER/DEMULTIPLEXER -40+85C SSOP-16 - OBSOLETE
8255A Programmable Peripheral Interface iAPX86 Family
8255A-5 12-Bit, 2.7 V to 5.25 V, 1.5 MSPS Low Power ADC; Package: SOIC - Wide; No of Pins: 24; Temperature Range: Industrial
82562G Mbps Platform LAN Connect
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
82-5590 制造商:Amphenol RF 功能描述:Connector Twinax Receptacle 0Hz to 500MHz Solder Straight Ca
825590-1 功能描述:手工工具 HANDTOOL FOR TIMER CONT RoHS:否 制造商:Molex 產(chǎn)品:Extraction Tools 類型: 描述/功能:Extraction tool
82-5590-2RFX 功能描述:RF 連接器 FRONT MNT BH RECEPT RoHS:否 制造商:Bomar Interconnect 產(chǎn)品:Connectors 射頻系列:BNC 型式:Jack (Female) 極性: 觸點電鍍:Gold 阻抗: 端接類型:Solder 主體類型:Straight Bulkhead 電纜類型:
82-5590-RFX 功能描述:RF 連接器 BULKHEAD JACK S/CUP FRONT MOUNT RoHS:否 制造商:Bomar Interconnect 產(chǎn)品:Connectors 射頻系列:BNC 型式:Jack (Female) 極性: 觸點電鍍:Gold 阻抗: 端接類型:Solder 主體類型:Straight Bulkhead 電纜類型:
825591 功能描述:手工工具 D.A. HANDTOOL ASSY RoHS:否 制造商:Molex 產(chǎn)品:Extraction Tools 類型: 描述/功能:Extraction tool