Section 7 Bus State Controller (BSC)
Rev. 2.00 Mar 09, 2006 page 270 of 906
REJ09B0292-0200
Bits 12 and 11—
CAS
-Before-
RAS
Refresh
RAS
Assert Time (TRAS1, TRAS0): These bits
specify the
RAS
assertion width when DRAM is connected.
Bit 12: TRAS1
Bit 11: TRAS0
Description
0
0
2 cycles
(Initial value)
1
3 cycles
1
0
4 cycles
1
5 cycles
After an auto-refresh command is issued, a bank active command is not issued for TRAS cycles,
regardless of the TRP bit setting. For synchronous DRAM, there is no
RAS
assertion period, but
there is a limit for the time from the issue of a refresh command until the next access. This value is
set to observe this limit. Commands are not issued for TRAS cycles when self-refresh is cleared.
Bit 12: TRAS1
Bit 11: TRAS0
Description
0
0
3 cycles
(Initial value)
1
4 cycles
1
0
6 cycles
1
9 cycles
Bit 10—Burst Enable (BE)
Bit 10: BE
Description
0
Burst disabled
(Initial value)
1
High-speed page mode during DRAM and ED0 interfacing is enabled
.
Burst access conditions are as follows:
•
Longword access, cache fill access, or DMAC 16-byte transfer, with 16-bit
bus width
•
Cache fill access or DMAC 16-byte transfer, with 32-bit bus width
During synchronous DRAM access, burst operation is always enabled
regardless of this bit
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 ...