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Functional Overview
2-30
Copyright © 2006 ARM Limited. All rights reserved.
ARM DDI 0389B
Note
In multiplexed-mode, both address and data are output by the SMC on the
smc_data_out_0[31:0]
output bus. Read data is accepted on the
smc_data_in_0[31:0]
bus.
Asynchronous write
Table 2-6 and Table 2-7 list the smc_opmode0_<0-3> and SRAM Register settings.
Figure 2-16 shows an asynchronous write with a write cycle time t
WC
of four cycles and
a
smc_we_n_0
assertion duration, t
WP
, of two cycles.
Note
The timing parameter t
WC
is controlling the deassertion of
smc_we_n_0
. You can use
it to vary the hold time of
smc_cs_n_0[3:0]
,
smc_add_0[31:0]
and
smc_data_out_0[31:0]
. This differs from the read case where the timing parameter
t
CEOE
controls the delay in the assertion of
smc_oe_n_0
. Additionally,
smc_we_n_0
is
always asserted one cycle after
smc_cs_n_0[3:0]
to ensure the address bus is valid.
Figure 2-16 Asynchronous write
Table 2-6 Asynchronous write opmode chip register settings
Field
mw
rd_sync
rd_bl
wr_sync
wr_bl
baa
adv
bls
ba
Value
-
-
-
b0
b000
-
-
-
-
Table 2-7 Asynchronous write SRAM cycles register settings
Field
t_rc
t_wc
t_ceoe
t_wp
t_pc
t_tr
Value
-
b0100
-
b010
-
-
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Summary of Contents for PrimeCell PL241
Page 20: ...Introduction 1 6 Copyright 2006 ARM Limited All rights reserved ARM DDI 0389B ...
Page 60: ...Functional Overview 2 40 Copyright 2006 ARM Limited All rights reserved ARM DDI 0389B ...
Page 94: ...Device Driver Requirements 5 6 Copyright 2006 ARM Limited All rights reserved ARM DDI 0389B ...
Page 104: ...Signal Descriptions A 10 Copyright 2006 ARM Limited All rights reserved ARM DDI 0389B ...
Page 110: ...Glossary Glossary 6 Copyright 2006 ARM Limited All rights reserved ARM DDI 0389B ...