Functional Overview

VPFBPFON

 

 

VPFBFONBRXWB>@

 

 

VPFBIEFONBLQB

 

 

VPFBDGGB>@

$''5$

$''5%

VPFBFVBQB>@

 

 

 

 

W75 

VPFBDGYBQB

 

 

VPFBRHBQB

 

 

VPFBZHBQB

 

 

GDWD

 

'%

 

'$

'$

VPFBGDWDBHQB

'$

'$

GDWD

 

 

UHDGBGDWD

 

'$

 

'$

'$

 

'$

Figure 2-23 Synchronous read and asynchronous write

Programming tRC and tWC when the controller operates in synchronous mode

For tRC:

when using memory devices that are not wait-enabled, you must program tRC to be the number of clock cycles required before valid data is available following the assertion of cs_n

when using memory devices that are wait-enabled, you must program tRC to be the number of clock cycles required before wait is active and stable, following the assertion of cs_n. That is:

t_RC = 3 + t_CEOE

Note

t_CEOE is only required if wait is asserted when oe_n goes LOW.

2-38

Copyright © 2006 ARM Limited. All rights reserved.

ARM DDI 0389B

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Image 58
SMC Networks PL241, AHB SRAM/NOR manual TCEOE is only required if wait is asserted when oen goes LOW