H8SX1663 datasheet(333/1158 Pages) RENESAS

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Section 6 Bus Controller (BSC)

Rev.1.00 Jun. 07, 2006 Page 281 of 1102

REJ09B0294-0100

(3) Refresh and All-Module Clock Stop Mode

This LSI is entered in all-module clock stop mode by the following operation: Stop the clocks of

all on-chip peripheral modules by setting the ACSE bit in MSTPCR to 1 (MSTPCRA, MSTPCRB

= H'FFFFFFFF) or run only the 8-bit timer (MSTPCRA, MSTPCRB = H'F[C to F]FFFFFF), then

execute the SLEEP instruction to enter the sleep mode.

In all-module clock stop mode, clocks for the bus controller and I/O ports are stopped. Since the

clock for the bus controller is stopped, an auto-refresh cycle cannot be performed. When external

SDRAM is used and the contents of the SDRAM in sleep mode should be held, clear the ACSE bit

in MSTPCE to 0.

For details, see section 23.2.2, Module Stop Control Registers A and B (MSTPCR and

MSTPCRB).

6.11.14

Setting SDRAM Mode Register

To use SDRAM, the mode register must be specified after a power-on reset.

Setting the MRSE bit in SDCR to 1 enables the SDRAM mode register setting. After this, write to

the SDRAM space in bytes.

When the value to be set in the SDRAM mode register is x, write to the following memory

location (address). The value of x is written to the SDRAM mode register.

• H'4000000/H'400000 + x for 8-bit bus SDRAM

• H'4000000/H'400000 + 2x for 16-bit bus SDRAM

The SDRAM mode register latches the address signals when the MRS command is issued.

This LSI does not support the burst read/burst write mode of SDRAM. When setting the SDRAM

mode register, use the burst read/single write mode and set the burst length to 1. Setting in the

SDRAM mode register must be consistent with that in the bus controller.

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