Section 12 DDR-SDRAM Interface (DDRIF)
Rev. 1.00 Oct. 01, 2007 Page 434 of 1956
REJ09B0256-0100
5. Whether the DDR-SDRAM enters the self-refresh mode can be checked by reading the SELFS
bit in MIM.
[Recovery from self-refresh state]
1. Clear the RMODE and DRE bits in MIM to 0 to clear the self-refresh state.
2. Whether the DDR-SDRAM recovers from the self-refresh mode can be checked by reading the
SELFS bit in MIM.
3. After the self-refresh state is cleared, wait for the time required by the DDR-SDRAM before
accessing the DDR-SDRAM (130 ns before issuing a command other than read and 200 clock
cycles before issuing a read command).
4. When access becomes possible, use the SMS bits in SCR to issue the REFA command so that
the concentrated refresh (REFA) is performed on all memory rows.
5. Dummy read a byte from any address.
6. Use the SMS bits in SCR to issue the PREALL command.
7. Use the SMS bits in SCR to issue the REFA command. This operation is required to make the
delay adjustment unit in the memory controller operate.
8. Set MIM so that the counter for the auto-refresh function starts counting and thus drives auto-
refreshing at a regular interval. After this, normal memory access is possible.
(2) Power-Down Mode (when CKE Goes Low)
When the PCKE bit in MIM is set, the CKE pin level is automatically changed and the DDR-
SDRAM then enters or leaves the power-down mode. This mode reduces DDR-SDRAM power
consumption.
Since the DDR-SDRAM enters the power-down mode after a memory access and leaves the
power-down mode before a memory access, an overhead of one cycle in the external memory
clock occurs in each case.
12.5.6
Registers that Set DDR-SDRAM Timing Restrictions
Registers that support connection to memory other than the DDR-SDRAM in a conventional
microcomputer and registers that set timing restrictions for the DDR-SDRAM of the DDRIF differ
with regard to the setting of the memory timing restrictions. The DDRIF registers are specialized
with respect to the DDR-SDRAM timing restrictions. For details, see section 12.4, Register
Descriptions.
Содержание SH7763
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Страница 122: ...Section 2 Programming Model Rev 1 00 Oct 01 2007 Page 56 of 1956 REJ09B0256 0100 ...
Страница 144: ...Section 3 Instruction Set Rev 1 00 Oct 01 2007 Page 78 of 1956 REJ09B0256 0100 ...
Страница 170: ...Section 4 Pipelining Rev 1 00 Oct 01 2007 Page 104 of 1956 REJ09B0256 0100 ...
Страница 282: ...Section 7 Caches Rev 1 00 Oct 01 2007 Page 216 of 1956 REJ09B0256 0100 ...
Страница 378: ...Section 9 Interrupt Controller INTC Rev 1 00 Oct 01 2007 Page 312 of 1956 REJ09B0256 0100 ...
Страница 514: ...Section 12 DDR SDRAM Interface DDRIF Rev 1 00 Oct 01 2007 Page 448 of 1956 REJ09B0256 0100 ...
Страница 630: ...Section 13 PCI Controller PCIC Rev 1 00 Oct 01 2007 Page 564 of 1956 REJ09B0256 0100 ...
Страница 686: ...Section 14 Direct Memory Access Controller DMAC Rev 1 00 Oct 01 2007 Page 620 of 1956 REJ09B0256 0100 ...
Страница 710: ...Section 16 Clock Pulse Generator CPG Rev 1 00 Oct 01 2007 Page 644 of 1956 REJ09B0256 0100 ...
Страница 732: ...Section 17 Watchdog Timer and Reset WDT Rev 1 00 Oct 01 2007 Page 666 of 1956 REJ09B0256 0100 ...
Страница 752: ...Section 18 Power Down Mode Rev 1 00 Oct 01 2007 Page 686 of 1956 REJ09B0256 0100 ...
Страница 772: ...Section 19 Timer Unit TMU Rev 1 00 Oct 01 2007 Page 706 of 1956 REJ09B0256 0100 ...
Страница 824: ...Section 21 Compare Match Timer CMT Rev 1 00 Oct 01 2007 Page 758 of 1956 REJ09B0256 0100 ...
Страница 1060: ...Section 23 Gigabit Ethernet Controller GETHER Rev 1 00 Oct 01 2007 Page 994 of 1956 REJ09B0256 0100 ...
Страница 1062: ...Section 24 IP Security Accelerator SECURITY Rev 1 00 Oct 01 2007 Page 996 of 1956 REJ09B0256 0100 ...
Страница 1124: ...Section 26 I 2 C Bus Interface IIC Rev 1 00 Oct 01 2007 Page 1058 of 1956 REJ09B0256 0100 ...
Страница 1184: ...Section 27 Serial Communication Interface with FIFO SCIF Rev 1 00 Oct 01 2007 Page 1118 of 1956 REJ09B0256 0100 ...
Страница 1350: ...Section 30 SIM Card Module SIM Rev 1 00 Oct 01 2007 Page 1284 of 1956 REJ09B0256 0100 ...
Страница 1484: ...Section 33 Audio Codec Interface HAC Rev 1 00 Oct 01 2007 Page 1418 of 1956 REJ09B0256 0100 ...
Страница 1560: ...Section 35 USB Host Controller USBH Rev 1 00 Oct 01 2007 Page 1494 of 1956 REJ09B0256 0100 ...
Страница 1720: ...Section 37 LCD Controller LCDC Rev 1 00 Oct 01 2007 Page 1654 of 1956 REJ09B0256 0100 ...
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