SMC Networks AHB SRAM/NOR smcmsync0, smcrstbypass, smcuseebi, Reference Manual, Format block

Models: AHB SRAM/NOR PL241

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smc_msync0

Functional Overview

smc_msync0

When HIGH, indicates smc_mclk0 is synchronous to smc_aclk. Otherwise they are asynchronous. Ensure that smc_msync0 is tied to the same value as smc_async0.

smc_rst_bypass

Use this signal for ATPG testing only. Tie it LOW for normal operation.

smc_use_ebi

When HIGH, indicates that the SMC must operate with a PrimeCell EBI.

See the ARM PrimeCell External Bus Interface (PL220) Technical

Reference Manual.

2.4.4APB slave interface operation

To enable a clean registered interface to the external infrastructure, the APB interface always adds a wait state for all reads and writes by driving pready LOW during the first cycle of the access phase.

In two instances, a delay of more than one wait state can be generated:

when a direct command is received and there are outstanding commands that prevent a new command being stored in the command FIFO

when an APB access is received and a previous direct command has not completed.

2.4.5Format block

This section describes:

Hazard handling

SRAM memory accesses on page 2-20.

Hazard handling

There are four types of hazard:

Read After Read (RAR)

Write After Write (WAW)

Read After Write (RAW)

Write After Read (WAR).

The AHB interface deals with RAW hazards. WAR hazards do not occur in the AHB.

ARM DDI 0389B

Copyright © 2006 ARM Limited. All rights reserved.

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SMC Networks AHB SRAM/NOR smcmsync0, smcrstbypass, smcuseebi, See the ARM PrimeCell External Bus Interface PL220 Technical