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Functional Overview
2-12
Copyright © 2006 ARM Limited. All rights reserved.
ARM DDI 0389B
Static memory clocking options
Table 2-1 lists the static memory clocking options.
2.3.4
Low-power interface operation
The memory controller has two low-power interfaces. These interfaces indicate whether
the clock for a specific domain can be switched off to reduce power consumption. It is
expected that these interfaces are controlled by a system clock controller. One interface
controls each of the following domains:
•
AHB clock domain
•
static memory clock domain.
Each domain uses a simple three signal interface to indicate whether the clocks are
required. The signals consist of:
a request input
<domain>_csyreq
an acknowledge output
<domain>_csysack
Table 2-1 Static memory clocking options
Options
Tie-off values
Fully synchronous
hclk = smc_mclk0
smc_async0
=
smc_msync0
= 1
smc_a_gt_m0_sync
= 0
Synchronous multiples
hclk
= n x
smc_mclk0
where:
n = integer value
smc_async0
=
smc_msync0
= 1
smc_a_gt_m0_sync
= 0
m x
hclk
=
smc_mclk0
where:
m = integer value
smc_async0
=
smc_msync0
= 1
smc_a_gt_m0_sync
= 1
Asynchronous
Extra registers are used to avoid metastability when
crossing the asynchronous clock boundary.
smc_async0 = smc_msync0
= 0
smc_a_gt_m0_sync
= 0
Содержание PrimeCell PL241
Страница 20: ...Introduction 1 6 Copyright 2006 ARM Limited All rights reserved ARM DDI 0389B ...
Страница 60: ...Functional Overview 2 40 Copyright 2006 ARM Limited All rights reserved ARM DDI 0389B ...
Страница 94: ...Device Driver Requirements 5 6 Copyright 2006 ARM Limited All rights reserved ARM DDI 0389B ...
Страница 104: ...Signal Descriptions A 10 Copyright 2006 ARM Limited All rights reserved ARM DDI 0389B ...
Страница 110: ...Glossary Glossary 6 Copyright 2006 ARM Limited All rights reserved ARM DDI 0389B ...