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Section 12 Bus State Controller (BSC)
Rev. 4.00 Sep. 14, 2005 Page 365 of 982
REJ09B0023-0400
1. Auto-refreshing
Refreshing is performed at intervals determined by the input clock selected by bits CKS2 to
CKS0 in RTCSR, and the value set by in RTCOR. The value of bits CKS2 to CKS0 in
RTCOR should be set so as to satisfy the refresh interval stipulation for the synchronous
DRAM used. First make the settings for RTCOR, RTCNT, and the RMODE and RFSH bits in
SDCR, then make the CKS2 to CKS0 and RRC2 to RRC0 settings. When the clock is selected
by bits CKS2 to CKS0, RTCNT starts counting up from the value at that time. The RTCNT
value is constantly compared with the RTCOR value, and if the two values are the same, a
refresh request is generated and an auto-refresh is performed for the number of times specified
by the RRC2 to RRC0. At the same time, RTCNT is cleared to zero and the count-up is
restarted. Figure 12.29 shows the auto-refresh cycle timing.
After starting, the auto refreshing, PALL command is issued in the Tp cycle to make all the
banks to pre-charged state from active state when some bank is being pre-charged. Then REF
command is issued in the Trr cycle after inserting idle cycles of which number is specified by
the WTRP1 and WTRP0 bits in CS3WCR. A new command is not issued for the duration of
the number of cycles specified by the WTRC1 and WTRC0 bits in CS3WCR after the Trr
cycle. The WTRC1 and WTRC0 bits must be set so as to satisfy the SDRAM refreshing cycle
time stipulation (tRC). An idle cycle is inserted between the Tp cycle and Trr cycle when the
setting value of the WTRP1 and WTRP0 bits in CS3WCR is longer than or equal to 1 cycle.
Summary of Contents for HD6417641
Page 2: ...Rev 4 00 Sep 14 2005 Page ii of l...
Page 7: ...Rev 4 00 Sep 14 2005 Page vii of l...
Page 11: ...Rev 4 00 Sep 14 2005 Page xi of l USB Universal serial bus WDT Watch dog timer...
Page 12: ...Rev 4 00 Sep 14 2005 Page xii of l...
Page 28: ...Rev 4 00 Sep 14 2005 Page xxviii of l...
Page 204: ...Section 4 Clock Pulse Generator CPG Rev 4 00 Sep 14 2005 Page 154 of 982 REJ09B0023 0400...
Page 212: ...Section 5 Watchdog Timer WDT Rev 4 00 Sep 14 2005 Page 162 of 982 REJ09B0023 0400...
Page 228: ...Section 6 Power Down Modes Rev 4 00 Sep 14 2005 Page 178 of 982 REJ09B0023 0400...
Page 246: ...Section 8 X Y Memory Rev 4 00 Sep 14 2005 Page 196 of 982 REJ09B0023 0400...
Page 318: ...Section 11 User Break Controller UBC Rev 4 00 Sep 14 2005 Page 268 of 982 REJ09B0023 0400...
Page 454: ...Section 12 Bus State Controller BSC Rev 4 00 Sep 14 2005 Page 404 of 982 REJ09B0023 0400...
Page 504: ...Section 14 U Memory Rev 4 00 Sep 14 2005 Page 454 of 982 REJ09B0023 0400...
Page 566: ...Section 17 Compare Match Timer CMT Rev 4 00 Sep 14 2005 Page 516 of 982 REJ09B0023 0400...
Page 868: ...Section 21 A D Converter Rev 4 00 Sep 14 2005 Page 818 of 982 REJ09B0023 0400...
Page 914: ...Section 23 I O Ports Rev 4 00 Sep 14 2005 Page 864 of 982 REJ09B0023 0400...
Page 956: ...Section 24 List of Registers Rev 4 00 Sep 14 2005 Page 906 of 982 REJ09B0023 0400...
Page 1016: ...Section 25 Electrical Characteristics Rev 4 00 Sep 14 2005 Page 966 of 982 REJ09B0023 0400...
Page 1024: ...Appendix Rev 4 00 Sep 14 2005 Page 974 of 982 REJ09B0023 0400...
Page 1032: ...Rev 4 00 Sep 14 2005 Page 982 of 982 REJ09B0023 0400 X X Y data addressing 52 X Y memory 193...
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