Section 7 Bus State Controller (BSC)
Rev. 2.00 Mar 09, 2006 page 297 of 906
REJ09B0292-0200
output cycle Tc and the initial read data fetch cycle Td1 can be specified between 1 cycle and 4
cycles using the W21/W20 and W31/W30 bits in WCR1. The number of cycles at this time
corresponds to the number of CAS latency cycles of the synchronous DRAM. When 2 cycles or
more, a NOP command issue cycle Tw is inserted between the Tc cycle and the Td1 cycle. The
number of cycles in the precharge completion waiting cycle Tap is specified by bits TRP1 and
TRP0 in MCR. When CAS latency is 1, a Tap cycle comprising the number of cycles specified by
TRP1 and TRP0 is generated. When the CAS latency is 2 or more, a Tap cycle equal to the TRP
specification – 1 is generated. During the Tap cycle, no commands other than NOP are issued to
the same bank. Figure 7.23 (a) and (b) show examples of burst read timing when RCD1/RCD0 is
01, W31/W30 is 01, and TRP1/TRP0 is 01.
When the data width is 16 bits, 8 burst cycles are required for a 16-byte data transfer. The data
fetch cycle goes from Td1 to Td8.
Synchronous DRAM CAS latency is up to 3 cycles, but the CAS latency of the bus state controller
can be specified up to 4. This is so that circuits containing latches can be installed between
synchronous DRAMs and the chip.
Tr
Tc
CKIO
A24 –A11
A10
A9–A1
CS2
or
CS3
RAS
CAS
RD/
WR
DQMxx
D31–D0
DACKn
*
Td1
Td2
Td3
Td4
Tde
Tap
Note:
*
DACKn waveform when active-low is specified.
Figure 7.22 (a) Basic Burst Read Timing (Auto-Precharge) I
φφφφ
: E
φφφφ
other than 1 : 1
Содержание SH7616
Страница 10: ...Rev 2 00 Mar 09 2006 page x of xxvi ...
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 ...