DS31256 datasheet(136/183 Pages) MAXIM

部件名	DS31256

功能描述	256-Channel, High-Throughput HDLC Controller

PDF	183 Pages

Scroll/Zoom	100%

制造商	MAXIM [Maxim Integrated Products]

网页	https://www.maximintegrated.com/en.html

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136 / 183 page

DS31256 256-Channel, High-Throughput HDLC Controller

136 of 183

10.1.8 PCI Fast Back-to-Back

Fast back-to-back transactions are two consecutive bus transactions without the usually required idle

cycle (

PFRAME and PIRDY deasserted) between them. This can only occur when there is a guarantee

that there is not any contention on the signal lines. The PCI specification allows two types of fast back-

to-back transactions—those that access the same agent (Type 1) and those that do not (Type 2).

Figure 10-9 shows an example of a fast back-to-back transaction where no idle cycle exists. As a bus

master, the DS31256 cannot perform a Type 2 access. As a target, it can accept both types of fast back-

to-back transactions.

Figure 10-9. PCI Fast Back-To-Back

345

6789

data #1

Address

CMD

BE #1

PCLK

PFRAME

PAD

PCBE

PIRDY

PTRDY

PDEVSEL

data #2

BE #2

Address

data #1

CMD

BE #1

DS31256 数据表(PDF) 136 Page - Maxim Integrated Products