SH7751 Group, SH7751R Group
Section 13 Bus State Controller (BSC)
R01UH0457EJ0301 Rev. 3.01
Page 451 of 1128
Sep 24, 2013
Power-On Sequence:
In order to use synchronous DRAM, mode setting must first be performed
after powering on. To perform synchronous DRAM initialization correctly, the bus state controller
registers must first be set, followed by a write to the synchronous DRAM mode register. In
synchronous DRAM mode register setting, the address signal value at that time is latched by a
combination of the
RAS
,
CAS
, and RD/
WR
signals. If the value to be set is X, the bus state
controller provides for value X to be written to the synchronous DRAM mode register by
performing a write to address H'FF X for area 2 synchronous DRAM, and to address
H'FF X for area 3 synchronous DRAM. In this operation the data is ignored, but the
mode write is performed as a byte-size access. To set burst read/burst write, CAS latency 1 to 3,
wrap type = sequential, and burst length 4, 8
*
, supported by this LSI, arbitrary data is written by
byte-size access to the following addresses.
Bus Width
CAS Latency
Area 2
Area 3
32 4 1
H'FF900048
H'FF940048
2
H'FF900088
H'FF940088
3
H'FF9000C8
H'FF9400C8
32 8
*
1
H'FF90004C
H'FF94004C
2
H'FF90008C
H'FF94008C
3
H'FF9000CC
H'FF9400CC
Note:
*
SH7751R
only
The value set in MCR.MRSET is used to select whether a precharge all banks command or a
mode register setting command is issued. The timing for the precharge all banks command is
shown in figure 13.38 (1), and the timing for the mode register setting command in figure 13.38
(2).
Before mode register, a 200 µs idle time (depending on the memory manufacturer) must be
guaranteed after the power required for the synchronous DRAM is turned on. If the reset signal
pulse width is greater than this idle time, there is no problem in making the precharge all banks
setting immediately.
First, a precharge all banks (PALL) command is issued in the TRp1 cycle by performing a write to
address H'FF X or H'FF X while MCR.MRSET = 0. Next, the number of
dummy auto-refresh cycles specified by the manufacturer (usually 8) or more must be executed.
This is achieved automatically while various kinds of initialization are being performed after auto-
refresh setting, but a way of carrying this out more dependably is to change the RTCOR register
value to set a short refresh request generation interval just while these dummy cycles are being
executed. With simple read or write access, the address counter in the synchronous DRAM used
for auto-refreshing is not initialized, and so the cycle must always be an auto-refresh cycle. After
Содержание SH7751 Group
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Страница 226: ...Section 5 Exceptions SH7751 Group SH7751R Group Page 172 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 264: ...Section 7 Instruction Set SH7751 Group SH7751R Group Page 210 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 320: ...Section 9 Power Down Modes SH7751 Group SH7751R Group Page 266 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 344: ...Section 10 Clock Oscillation Circuits SH7751 Group SH7751R Group Page 290 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 388: ...Section 12 Timer Unit TMU SH7751 Group SH7751R Group Page 334 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 800: ...Section 17 Smart Card Interface SH7751 Group SH7751R Group Page 746 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 848: ...Section 19 Interrupt Controller INTC SH7751 Group SH7751R Group Page 794 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 876: ...Section 20 User Break Controller UBC SH7751 Group SH7751R Group Page 822 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 1036: ...Section 22 PCI Controller PCIC SH7751 Group SH7751R Group Page 982 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 1152: ...Appendix C Mode Pin Settings SH7751 Group SH7751R Group Page 1098 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
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Страница 1186: ... SH7751 Group SH7751R Group User s Manual Hardware R01UH0457EJ0301 Previous Number REJ09B0370 0400 ...