Renesas SH7781 User Manual

Page 439

11. Local Bus State Controller (LBSC)

Rev.1.00 Jan. 10, 2008 Page 409 of 1658

REJ09B0261-0100

When software wait insertion is specified by CSnWCR, the external wait input signal,

RDY, is

also sampled. The

RDY signal sampling timing is shown in figure 11.10, where a single wait cycle

is specified as a software wait. The

RDY signal is sampled at the transition from the Tw state to

the T2 state. Therefore, the assertion of the

RDY signal has no effect in the T1 cycle or in the first

Tw cycle. The

RDY signal is sampled on the rising edge of the clock.

CLKOUT

A25 to A0

CSn

RD
(In reading)

D31 to D0
(In reading)

WEn
(In writing)

D31 to D0
(In writing)

Twe

RDY

DACKn

In this example, DACKn is active-high. (The circles indicate the sampling timing.)

: Sampling Timing

Figure 11.10 SRAM Interface Wait Timing

(Wait Cycle Insertion by

RDY Signal, RDY Signal Is Synchronous Input)