H8SX1663 datasheet(301/1158 Pages) RENESAS

Part #	H8SX1663

Description	Renesas 32-Bit CISC Microcomputer H8SX Family / H8SX/1600 Series

PDF	1158 Pages

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Manufacturer	RENESAS [Renesas Technology Corp]

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Section 6 Bus Controller (BSC)

Rev.1.00 Jun. 07, 2006 Page 249 of 1102

REJ09B0294-0100

(2) Self-Refresh Mode

Some DRAMs have a self-refresh mode (battery backup mode). The self-refresh mode is a kind of

standby mode and refresh timing and refresh address are controlled internally.

The self-refresh mode is selected by setting the RFSHE and SLFRF bits in REFCR to 1. The CAS

and RAS signals are output as shown in figure 6.56 by executing the SLEEP instruction. Then,

DRAM enters self-refresh mode.

When a CBR refresh is requested on a transition to the standby mode, the CBR refresh is first

performed and then the self-refresh mode is entered.

When the self-refresh mode is used, do not clear the OPE bit in SBYCR to 0.

For details, see section 23.2.1, Standby Control Register (SBYCR).

TRp

TRr

TRc3

RAS

LUCAS

LLCAS

RD/

High

Software

standby

TRc4

High

Figure 6.56 Self-Refresh Timing

H8SX1663 Datasheet(PDF) 301 Page - Renesas Technology Corp