SMC Networks AHB SRAM/NOR, PL241 manual Functional operation, SMC functional operation on page

Models: AHB SRAM/NOR PL241

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2.3Functional operation

Functional Overview

2.3Functional operation

This section is divided into:

AHB interface operation

AHB to APB bridge operation on page 2-10

Clock domain operation on page 2-11

Low-power interface operation on page 2-12

SMC functional operation on page 2-15.

2.3.1AHB interface operation

This section describes:

AHB fixed burst types

Undefined length INCR bursts on page 2-8

Broken bursts on page 2-8

Bufferable bit of the HPROT signal on page 2-8

Read after write hazard detection buffer on page 2-9

AHB response signals on page 2-9

Locked transfers on page 2-9

Registered HWDATA on page 2-10

Big-endian32-bit mode on page 2-10

Removal of AHB error response logic on page 2-10.

AHB fixed burst types

All AHB fixed length bursts directly map to burst types that the internal interconnect uses. The internal interconnect and the memory controller are based on transferring bursts of data. The larger the burst size, the more efficient the transfer and overall performance. The standard AHB fixed length burst types are directly mapped to the internal protocol.

Burst operation has performance benefits because when the first beat of a burst is accepted, it contains data about the remaining beats. For example, from the first beat of a read burst, all the data required to complete the transfer can be read from memory. This first transfer has some delay before data is returned. Subsequent beats of the burst can have less delay because the data they require might have already been read from the memory.

ARM DDI 0389B

Copyright © 2006 ARM Limited. All rights reserved.

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SMC Networks AHB SRAM/NOR, PL241 manual Functional operation, AHB interface operation AHB to APB bridge operation on page