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SH7751 Group, SH7751R Group
Section 13 Bus State Controller (BSC)
R01UH0457EJ0301 Rev. 3.01
Page 411 of 1128
Sep 24, 2013
When software wait insertion is specified by WCR2, the external wait input
RDY
signal is also
sampled.
RDY
signal sampling is shown in figure 13.11. A single-cycle wait is specified as a
software wait. Sampling is performed at the transition from the Tw state to the T2 state; therefore,
the
RDY
signal has no effect if asserted in the T1 cycle or the first Tw cycle. The
RDY
signal is
sampled on the rising edge of the clock.
T1
CKIO
A25–A0
CSn
RD/
WR
RD
(read)
D31–D0
(read)
WEn
(write)
D31–D0
(write)
BS
Tw
Twe
T2
RDY
DACKn
(SA: IO
→
memory)
DACKn
(SA: IO
←
memory)
DACKn
(DA)
Note: For DACKn, an example is shown where CHCRn.AL (access level) = 0 for the DMAC.
Figure 13.11 SRAM Interface Wait State Timing (Wait State Insertion by
RDY
Signal)