12. DDR2-SDRAM Interface (DBSC2)
Rev.1.00 Jan. 10, 2008 Page 485 of 1658
REJ09B0261-0100
Bit Bit
Name
Initial
Value R/W
Description
2 to 0
CMD2 to
CMD0
000
R/W
SDRAM Command Issue Bit
These bits are used to issue commands necessary to
execute the DDR2-SDRAM initialization sequence and
self-refresh transition/cancellation. When these bits are
written, the command corresponding to the written value
is issued once. For example, in order to issue the auto-
refresh command twice, it would be necessary to write
100 to these bits twice. The precharge interval,
minimum interval between auto-refresh and the next
command, and other intervals are values set in the
SDRAM timing register, described below. When read,
these bits are always read as 000.
Once writing is performed to enable the MCKE signal, it
remains enabled. During self-refresh control, the MCKE
goes to low level, but on cancellation MCKE
automatically returns to high level.
For details on the MCKE signal operation, refer to
section 12.5.13, Regarding MCKE Signal Operation.
000: Normal operation (power-on reset)
001: Setting prohibited (Correct operation cannot be
guaranteed.)
010: Precharge (PALL) command issued
011: The MCKE signal is enabled (high level).
100: Auto-refresh (REF) command issued
101 to 111: Setting prohibited (Correct operation cannot
be guaranteed.)
Note: This register can be written only when automatic issue of auto-refresh is disabled (the
ARFEN bit in the DBRFCNT0 register is cleared to 0).
Summary of Contents for SH7781
Page 4: ...Rev 1 00 Jan 10 2008 Page iv of xxx REJ09B0261 0100 ...
Page 74: ...2 Programming Model Rev 1 00 Jan 10 2008 Page 44 of 1658 REJ09B0261 0100 ...
Page 272: ...8 Caches Rev 1 00 Jan 10 2008 Page 242 of 1658 REJ09B0261 0100 ...
Page 376: ...10 Interrupt Controller INTC Rev 1 00 Jan 10 2008 Page 346 of 1658 REJ09B0261 0100 ...
Page 694: ...13 PCI Controller PCIC Rev 1 00 Jan 10 2008 Page 664 of 1658 REJ09B0261 0100 ...
Page 762: ...14 Direct Memory Access Controller DMAC Rev 1 00 Jan 10 2008 Page 732 of 1658 REJ09B0261 0100 ...
Page 788: ...15 Clock Pulse Generator CPG Rev 1 00 Jan 10 2008 Page 758 of 1658 REJ09B0261 0100 ...
Page 828: ...17 Power Down Mode Rev 1 00 Jan 10 2008 Page 798 of 1658 REJ09B0261 0100 ...
Page 846: ...18 Timer Unit TMU Rev 1 00 Jan 10 2008 Page 816 of 1658 REJ09B0261 0100 ...
Page 1292: ...24 Multimedia Card Interface MMCIF Rev 1 00 Jan 10 2008 Page 1262 of 1658 REJ09B0261 0100 ...
Page 1326: ...25 Audio Codec Interface HAC Rev 1 00 Jan 10 2008 Page 1296 of 1658 REJ09B0261 0100 ...
Page 1482: ...28 General Purpose I O Ports GPIO Rev 1 00 Jan 10 2008 Page 1452 of 1658 REJ09B0261 0100 ...
Page 1538: ...30 User Debugging Interface H UDI Rev 1 00 Jan 10 2008 Page 1508 of 1658 REJ09B0261 0100 ...
Page 1688: ...Appendix Rev 1 00 Jan 10 2008 Page 1658 of 1658 REJ09B0261 0100 ...
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Page 1692: ...SH7785 Hardware Manual ...