日韩欧美另类亚洲中文字幕,成年人视频网站在线观看亚洲,欧美一级xxx

<strike id="tivgx"><nobr id="tivgx"></nobr></strike>

您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄25633 > MT80C31-25R (TEMIC SEMICONDUCTORS) 8-BIT, 25 MHz, MICROCONTROLLER, PQFP44 PDF資料下載

型號：	MT80C31-25R
廠商：	TEMIC SEMICONDUCTORS
元件分類：	微控制器/微處理器
英文描述：	8-BIT, 25 MHz, MICROCONTROLLER, PQFP44
文件頁數(shù)：	619/1447頁
文件大?。?/td>	3788K
代理商：	MT80C31-25R

6437E–ATARM–23-Apr-13

Multi-port Functionality

The SDRAM protocol imposes a check of timings prior to performing a read or a write access,

thus decreasing the performance of systems. An access to SDRAM is performed if banks and

rows are open (or active). To activate a row in a particular bank, it has to de-active the last open

row and open the new row. Two SDRAM commands must be performed to open a bank: Pre-

charge and Active command with respect to Trp timing. Before performing a read or write

command, Trcd timing must checked.

This operation represents a significative loss. (see Figure 22-24).

Figure 22-24. Trp and Trcd Timings

The multi-port controller has been designed to mask these timings and thus improve the band-

width of the system.

DDRSDRC is a multi-port controller since four masters can simultaneously reach the controller.

This feature improves the bandwidth of the system because it can detect four requests on the

AHB slave inputs and thus anticipate the commands that follow, PRECHARGE and ACTIVE

commands in bank X during current access in bank Y. This allows Trp and Trcd timings to be

masked (see Figure 22-25). In the best case, all accesses are done as if the banks and rows

were already open. The best condition is met when the four masters work in different banks. In

the case of four simultaneous read accesses, when the four banks and associated rows are

open, the controller reads with a continuous flow and masks the cas latency for each different

access. To allow a continuous flow, the read command must be set at 2 or 3 cycles (cas latency)

before the end of current access. This requires that the scheme of arbitration changes since the

round-robin arbitration cannot be respected. If the controller anticipates a read access, and thus

before the end of current access a master with a high priority arises, then this master will not

The arbitration mechanism reduces latency when conflicts occur, i.e., when two or more masters

try to access the SDRAM device at the same time.

4 cycles before performing a read command

相關PDF資料	PDF描述
MQ80C52TXXX-16/883	8-BIT, MROM, 16 MHz, MICROCONTROLLER, CQFP44
MR80C52EXXX-20SCD	8-BIT, MROM, 20 MHz, MICROCONTROLLER, CQCC44
MR80C32-16SHXXX	8-BIT, 16 MHz, MICROCONTROLLER, CQCC44
MD80C32EXXX-30/883	8-BIT, 30 MHz, MICROCONTROLLER, CDIP40
MR80C32E-16SC	8-BIT, 16 MHz, MICROCONTROLLER, CQCC44

相關代理商/技術參數(shù)	參數(shù)描述
MT80C31BH	制造商:Rochester Electronics LLC 功能描述:- Bulk 制造商:Intel 功能描述:
MT80C51BH	制造商:ROCHESTER 制造商全稱:ROCHESTER 功能描述:CMOS SINGLE - CHIP 8-BIT MICROCOMPUTER 64K program Memory Space
MT80C51FB	制造商:Rochester Electronics LLC 功能描述:- Bulk
MT80C51FB/B	制造商:Intel 功能描述:
MT80GB	制造商:Datak Corporation 功能描述:

發(fā)布緊急采購，3分鐘左右您將得到回復。

(若只采購一條型號，填寫一行即可)

*型號	*數(shù)量	廠商	批號	封裝