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Section 12 Bus State Controller (BSC)
Rev. 4.00 Sep. 14, 2005 Page 331 of 982
REJ09B0023-0400
12.5.4
CSn
Assert Period Expansion
The number of cycles from
CSn
assertion to
RD
,
WEn
assertion can be specified by setting bits
SW1 and SW0 in CSnWCR. The number of cycles from
RD
,
WEn
negation to
CSn
negation can
be specified by setting bits HW1 and HW0. Therefore, a flexible interface to an external device
can be obtained. Figure 12.11 shows an example. A Th cycle and a Tf cycle are added before and
after an ordinary cycle, respectively. In these cycles,
RD
and
WEn
are not asserted, while other
signals are asserted. The data output is prolonged to the Tf cycle, and this prolongation is useful
for devices with slow writing operations.
T1
CKIO
A25 to A0
CSn
RD/
WR
RD
D31 to D0
WEn
D31 to D0
BS
Th
Read
Write
T2
DACKn
*
Tf
Note:
*
The waveform for
DACKn
is when active low is specified.
Figure 12.11
CSn
Assert Period Expansion
Summary of Contents for HD6417641
Page 2: ...Rev 4 00 Sep 14 2005 Page ii of l...
Page 7: ...Rev 4 00 Sep 14 2005 Page vii of l...
Page 11: ...Rev 4 00 Sep 14 2005 Page xi of l USB Universal serial bus WDT Watch dog timer...
Page 12: ...Rev 4 00 Sep 14 2005 Page xii of l...
Page 28: ...Rev 4 00 Sep 14 2005 Page xxviii of l...
Page 204: ...Section 4 Clock Pulse Generator CPG Rev 4 00 Sep 14 2005 Page 154 of 982 REJ09B0023 0400...
Page 212: ...Section 5 Watchdog Timer WDT Rev 4 00 Sep 14 2005 Page 162 of 982 REJ09B0023 0400...
Page 228: ...Section 6 Power Down Modes Rev 4 00 Sep 14 2005 Page 178 of 982 REJ09B0023 0400...
Page 246: ...Section 8 X Y Memory Rev 4 00 Sep 14 2005 Page 196 of 982 REJ09B0023 0400...
Page 318: ...Section 11 User Break Controller UBC Rev 4 00 Sep 14 2005 Page 268 of 982 REJ09B0023 0400...
Page 454: ...Section 12 Bus State Controller BSC Rev 4 00 Sep 14 2005 Page 404 of 982 REJ09B0023 0400...
Page 504: ...Section 14 U Memory Rev 4 00 Sep 14 2005 Page 454 of 982 REJ09B0023 0400...
Page 566: ...Section 17 Compare Match Timer CMT Rev 4 00 Sep 14 2005 Page 516 of 982 REJ09B0023 0400...
Page 868: ...Section 21 A D Converter Rev 4 00 Sep 14 2005 Page 818 of 982 REJ09B0023 0400...
Page 914: ...Section 23 I O Ports Rev 4 00 Sep 14 2005 Page 864 of 982 REJ09B0023 0400...
Page 956: ...Section 24 List of Registers Rev 4 00 Sep 14 2005 Page 906 of 982 REJ09B0023 0400...
Page 1016: ...Section 25 Electrical Characteristics Rev 4 00 Sep 14 2005 Page 966 of 982 REJ09B0023 0400...
Page 1024: ...Appendix Rev 4 00 Sep 14 2005 Page 974 of 982 REJ09B0023 0400...
Page 1032: ...Rev 4 00 Sep 14 2005 Page 982 of 982 REJ09B0023 0400 X X Y data addressing 52 X Y memory 193...
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