H8SX1663 datasheet(278/1158 Pages) RENESAS

Il numero della parte	H8SX1663

Spiegazioni elettronici	Renesas 32-Bit CISC Microcomputer H8SX Family / H8SX/1600 Series

PDF	1158 Pages

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Produttore elettronici	RENESAS [Renesas Technology Corp]

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Section 6 Bus Controller (BSC)

Rev.1.00 Jun. 07, 2006 Page 226 of 1102

REJ09B0294-0100

When consecutively reading from the same area connected to a peripheral LSI whose data hold

time is long, data outputs from the peripheral LSI and this LSI may conflict. Inserting the chip

select assertion period extension cycle after the access cycle can avoid the data conflict.

Figure 6.36 shows an example of the operation. In the figure, both bus cycles A and B are read

access cycles to the address/data multiplexed I/O space. An example of the data conflict is shown

in (a), and an example of avoiding the data conflict by the

CS assertion period extension cycle in

(b).

Address bus

Data bus

Bus cycle A

Bus cycle B

(a) Without

CS assertion period extension cycle (CSXTn = 0)

(b) With

CS assertion period extension cycle (CSXTn = 1)

Data hold time is long.

Data conflict

Address bus

Data bus

Bus cycle A

Bus cycle B

Figure 6.36 Consecutive Read Accesses to Same Area

(Address/Data Multiplexed I/O Space)

H8SX1663 Scheda tecnica(PDF) 278 Page - Renesas Technology Corp