Section 7 Bus State Controller (BSC)
Rev. 2.00 Mar 09, 2006 page 322 of 906
REJ09B0292-0200
Writing to address X + H'FFFF0000 or X + H'FFFF8000 first issues an all-bank precharge
command (PALL), then issues eight dummy auto-refresh commands (REF) required for the
synchronous DRAM power-on sequence. Lastly, a mode register write command (MRS) is issued.
Three idle cycles are inserted between the all-bank precharge command and the first auto-refresh
command, and eight idle cycles between auto-refresh commands, and between the eighth auto-
refresh command and the mode register write command, regardless of the MCR setting.
After writing to the synchronous DRAM mode register, perform a dummy read to each
synchronous DRAM bank before starting normal access. This will initialize the SH7616's internal
address comparator.
Synchronous DRAM requires a fixed idle time after powering on before the all-bank precharge
command is issued. Refer to the synchronous DRAM manual for the necessary idle time. When
the pulse width of the reset signal is longer than the idle time, the mode register may be set
immediately without problem. However, care is required if the pulse width of the reset signal is
shorter than the idle time.
Tp
Tpw
Tpw
Tpw
Trr
Trc
Trc
Trr
Trc
Trc
Tmw
CKIO
A24–A11
A10
A9–A1
CS2
or
CS3
RAS
CAS
RD/
WR
DQMxx
MRS
REF
REF
PALL
Figure 7.36 Synchronous DRAM Mode Write Timing
Содержание SH7616
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Страница 132: ...Section 2 CPU Rev 2 00 Mar 09 2006 page 106 of 906 REJ09B0292 0200 ...
Страница 568: ...Section 12 16 Bit Free Running Timer FRT Rev 2 00 Mar 09 2006 page 542 of 906 REJ09B0292 0200 ...
Страница 582: ...Section 13 Watchdog Timer WDT Rev 2 00 Mar 09 2006 page 556 of 906 REJ09B0292 0200 ...
Страница 662: ...Section 14 Serial Communication Interface with FIFO SCIF Rev 2 00 Mar 09 2006 page 636 of 906 REJ09B0292 0200 ...
Страница 706: ...Section 16 Serial I O SIO Rev 2 00 Mar 09 2006 page 680 of 906 REJ09B0292 0200 ...
Страница 820: ...Section 19 Pin Function Controller PFC Rev 2 00 Mar 09 2006 page 794 of 906 REJ09B0292 0200 ...
Страница 932: ...Appendix D Package Dimensions Rev 2 00 Mar 09 2006 page 906 of 906 REJ09B0292 0200 ...
Страница 935: ...SH7616 Hardware Manual ...