UPD98405 datasheet(18/64 Pages) NEC

18 / 64 page

Data Sheet S12689EJ2V0DS00

µµµµPD98405

<3>

Serial EEPROM interface signals

The

µPD98405 has a serial EEPROM interface supporting MICROWIRETM interface. Through this serial

EEPROM interface, the contents of the PCI configuration register can be loaded from an EEPROM connected.

Remark It is recommended that National Semiconductor’s “NM93C46” be connected as the EEPROM.

Pin Name

Pin No.

I/O

I/O Level

Function

E2PCS

234

TTL

EEPROM chip select.

This is a chip select signal for EEPROM.

E2PDI

231

TTL

EEPROM data input.

This signal is connected to the data output pin of the EEPROM.

This signal is internally pulled down.

E2PDO

232

TTL

EEPROM data output.

This signal is connected to the data input pin of the EEPROM.

E2PCLK

233

TTL

EEPROM clock.

This pin supplies the clock necessary for transferring data with

the EEPROM. It divides the clock input to the CLK pin by 36 for

output.

<4>

Expansion ROM interface signals.

The

µPD98405 has an expansion ROM interface as option.

Pin Name

Pin No.

I/O

I/O Level

Function

ROMA15-

ROMA0

200-207,

209-213,

215-217

TTL

ROM address.

These are address signals to access the 64K expansion ROM.

ROMD7-

ROMD0

218-225

TTL

ROM data.

These are expansion ROM data signals and are internally pulled

down.

ROMCS_B

226

TTL

ROM select.

This is a chip select signal for the expansion ROM.

ROMOE_B

230

TTL

ROM output enable.

This signal enables the output buffer of the expansion ROM

during a read operation.

UPD98405 Datasheet(PDF) 18 Page - NEC

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