Texas Instruments TNETX4090 specifications DIO interface, Eeprom interface

TNETX4090

ThunderSWITCH II 9-PORT 100-/1000-MBIT/S ETHERNET SWITCH

SPWS044E ± DECEMBER 1997 ± REVISED AUGUST 1999

Terminal Functions (Continued)

DIO interface

TERMINAL

I/O

INTERNAL

DESCRIPTION

NAME

NO.

RESISTOR

SAD0

AF22

DIO address bus. Selects the internal host registers provided

is high. Internal pullup

I

Pullup

SDMA

SAD1

AE22

resistors are provided.

DIO chip select. When low,

indicates a DIO port access is valid. An internal pullup resistor

AD22

I

Pullup

SCS

SCS

is provided.

SDATA0

AF20

SDATA1

AE20

SDATA2

AD20

SDATA3

AC20

I/O

Pullup

DIO data bus. Byte-wide bidirectional DIO port. External pullup resistors are required.

SDATA4

AF21

SDATA5

AE21

SDATA6

AD21

SDATA7

AC21

DIO DMA select. When low,

modifies the behavior of the DIO interface to allow it to

SDMA

operate efficiently with an external direct memory access (DMA) controller. SAD0 and SAD1 are

SDMA

AF24

I

Pullup

not used to select the internal host register for the access. Instead, the DIO address to access

internal registers is provided by the DMAAddress register, and one of two host register

addresses is selected according to dmainc in SysControl. An internal pullup resistor is provided.

SINT

AF19

O

None

Interrupt. Interrupt to the attached microprocessor. The interrupt type can be found in the Int

register.

DIO ready. When low during reads,

indicates to the host when data is valid to be read.

SRDY

AF23

O

Pullup

When low during writes, SRDY indicates when data has been received. SRDY is driven high

SRDY

for one clock cycle before placing the output in high impedance after SCS is taken high. An

internal pullup resistor is provided.

DIO read not write

SRNW

AC22

I

Pullup

± When high, read operation is selected.

± When low, write operation is selected.

An internal pullup resistor is provided.

Network management (NM) port, receive ready. When high, SRXRDY indicates that the NM

SRXRDY

AE23

O

None

port's receive buffers are completely empty and the NM port is able to receive a frame of any

size up to 1535 bytes in length.

Network management (NM) port, transmit ready. When high, STXRDY indicates that at least

STXRDY

AD23

O

None

one buffer of frame data is available to be read by the management CPU. It outputs a 1 if any

of the end-of-frame (eof), start-of-frame (sof), or interior-of-frame (iof) bits in NMTxControl is set

to 1, otherwise, it outputs 0.

EEPROM interface

TERMINAL

I/O

INTERNAL

DESCRIPTION

NAME

NO.

RESISTOR

ECLK

L26

O

None

EEPROM data clock. An internal pullup resistor is provided.

EDIO

M26

I/O

Pullup

EEPROM data input/output. An internal pullup resistor is provided.

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