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Renesas SH7641 User Manual

Page 330

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Section 12 Bus State Controller (BSC)

Rev. 4.00 Sep. 14, 2005 Page 280 of 982

REJ09B0023-0400

Bit Bit

Name

Initial
Value R/W Description

5 DMAIWA

0 R/W

Method

of

inserting

wait states between access cycles

when DMA single address transfer is performed.

Specifies the method of inserting the idle cycles
specified by the DMAIW[2:0] bit. Clearing this bit will
make this LSI insert the idle cycles when another
device, which includes this LSI, drives the data bus
after an external device with

DACK drove it. However,

when the external device with

DACK drives the data

bus continuously, idle cycles are not inserted. Setting
this bit will make this LSI insert the idle cycles after an
access to an external device with

DACK, even when

the continuous accesses to an external device with

DACK are performed.

0: Idle cycles inserted when another device drives the

data bus after an external device with

DACK drove

it.

1: Idle cycles always inserted after an access to an

external device with

DACK

4

 1

R

Reserved

This bit is always read as 1. The write value should
always be 1.

3

 0

R

Reserved

This bit is always read as 0. The write value should
always be 0.

2 CKD2RDV

0 R

CKIO2

Drive

Specifies whether the CKIO2 pin outputs a low level
signal or clock (B

φ). In clock mode 7 (CKIO pin input),

the CKIO2 pin has high impedance. The CK2DRV bit
setting is enabled in the 2 or 6 clock mode.

0: Outputs a low level signal

1: Outputs a clock (B

φ)

1 HIZMEM

0 R/W

High-Z

Memory

Control

Specifies the pin state in software standby mode for
A25 to A0,

BS, CS, RD/WR, WEn/DQNxx, RD, and

FRAME.

0: High impedance in standby mode.

1: Driven in standby mode

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