參數(shù)資料
型號: CDK8920A
廠商: Cirrus Logic, Inc.
英文描述: CRYSTAL LAN ISA PLUG-AND-PLAY ETHERNET CONTROLLER
中文描述: 水晶藍的ISA即插即用,即插即用以太網(wǎng)控制器
文件頁數(shù): 102/144頁
文件大?。?/td> 1229K
代理商: CDK8920A
5.5.9
RxDMA-Only Mode
Receive DMA Operation for
In an RxDMAOnly mode, a system DMA moves
all the received frames from the on-chip memory
to an external 16- or 64-Kbyte buffer memory.
The received frame must have passed the desti-
nation address filter, and must be completely
received. Usually the DMA receive frame inter-
rupt (RxDMAiE, bit 7, Register B, BufCFG) is
set so that the CS8920A generates an interrupt
when a frame is transferred by DMA. Figure 5.7
shows how a DMA Receive Frame interrupt is
processed.
In the interrupt service routine, the BufEvent
register (register C), bit RxDMA Frame (bit 7)
indicates that one or more receive frames were
transferred using DMA. The software driver
should maintain a pointer (e.g. PDMA_START)
that will point to the beginning of a new frame.
After the CS8920A is initialized and before any
frame is received, pointer P
DMA_START
points to
the beginning of the DMA buffer memory area.
The first read of the DMA Frame Count, C
DMA
,
commits the memory covered by the C
DMA
count, and the DMA cannot overwrite this com-
mitted space until the space is freed. The driver
then processes the frames described by the
C
DMA
count and makes a second read of the
DMA frame count. This second read frees the
buffer memory space described by the C
DMA
counter.
During the frame processing, the software should
advance the P
DMA_START
pointer. At the end of
processing a frame, pointer P
DMA_START
should
Process the
C
DMA
Frames
Read the DMA frame Count (C
DMA
)
(PacketPage base + 0028h)
No
C
DMA
= 0
Host Enters Interrupt Routine
Process other events
that caused interrupt
Yes
No
RxDMA
Frame
bit set
Process other events
that caused interrupt
Yes
Figure 5.7. RxDMA Only Operation
CS8920A
102
DS238PP2
相關(guān)PDF資料
PDF描述
CDL13005 NPN PLASTIC POWER TRANSISTOR
CDLL4150-1 SWITCHING DIODE
CDLL4567A Single Schmitt-Trigger Inverter 5-SOT-23 -40 to 85
CDLL4568 TEMPERATURE COMPENSATED ZENER REFERENCE DIODES
CDLL4568A Single Schmitt-Trigger Inverter 5-SC70 -40 to 85
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
CDKEIL 功能描述:開發(fā)軟件 Devel Software and Documention CD RoHS:否 制造商:Atollic Inc. 產(chǎn)品:Compilers/Debuggers 用于:ARM7, ARM9, Cortex-A, Cortex-M, Cortex-R Processors
CDKEIL-US 功能描述:開發(fā)軟件 DEVELOPMENT SOFTWARE AND DOCUMENTATION CD RoHS:否 制造商:Atollic Inc. 產(chǎn)品:Compilers/Debuggers 用于:ARM7, ARM9, Cortex-A, Cortex-M, Cortex-R Processors
CDKWM1804-S-1 功能描述:WM1804 - Audio, Audio Processing Evaluation Board 制造商:cirrus logic inc. 系列:- 零件狀態(tài):有效 主要用途:音頻,音頻處理 嵌入式:- 使用的 IC/零件:WM1804 主要屬性:- 輔助屬性:- 所含物品:板 標準包裝:1
CDKWM1811A-S-1 功能描述:WM1811A - Audio, CODEC Evaluation Board 制造商:cirrus logic inc. 系列:- 零件狀態(tài):有效 主要用途:音頻編解碼器 嵌入式:- 使用的 IC/零件:WM1811A 主要屬性:- 輔助屬性:- 所含物品:板 標準包裝:1
CDKWM5102-S-1 功能描述:WM5102 - Audio, CODEC Evaluation Board 制造商:cirrus logic inc. 系列:- 零件狀態(tài):有效 主要用途:音頻編解碼器 嵌入式:- 使用的 IC/零件:WM5102 主要屬性:- 輔助屬性:- 所含物品:板 標準包裝:1