DP83821 datasheet(6/86 Pages) NSC

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2.0 Pin Descriptions (Continued)

Note: DP83821 supports NM27LV010 for the ROM interface device.

TXER/TXD9

154

Transmit Error: This signal is synchronous to TXCLK and provides error

indications and also is used for 1000 Mb/s half-duplex carrier extension and

packet bursting functions. The DP83821 will only assert this signal in 1000 Mb/s

mode of operation.

TBI Transmit Data: In TBI mode, this is TXD9 of the 10-bit TBI Transmit data.

GTXCLK/

TXPMACLK

140

GMII transmit Clock: A continuous clock used for 1000 Mb/s. It is output to an

external PMD and is the reference clock for Transmit GMII signaling. The clock

frequency is 125 MHz.

TBI Transmit Clock: In TBI mode, this is the 125MHz transmit clock to an

external PMD and is the reference for Transmit TBI signaling.

REF125

137

125 MHz Reference Clock: May be optionally connected to a 125 MHz

oscillator for 1000 Mb/s mode. If not used should be tied high.

BIOS ROM/Flash Interface

Symbol

Pin No(s)

Direction

Description

MCSN

BIOS PROM/Flash Chip Select: During a BIOS ROM/Flash access, this

signal is used to select the ROM device.

MD7, MD6,

MD5, MD4/EEDO,

MD3, MD2,

MD1/CFGDISN,

MD0/PMGDISN

104, 103,

102, 101,

98, 97,

96,

95,

I/O

BIOS ROM/Flash Data Bus: During a BIOS ROM/Flash access these

signals are used to transfer data to or from the ROM/Flash device.

MD5:0 and MD7 pin pads have an internal weak pull up.

MD6 pin pad has an internal weak pull down.

MA15/TXD7,

MA14/TXD6,

MA13/TXD5,

MA12/TXD4,

MA11/TXD3,

MA10/TXD2,

MA9/TXD1,

MA8/TXD0,

MA7, MA6,

MA5, MA4/EECLK,

MA3/EEDI, MA2,

MA1, MA0

152,

151,

148,

147,

146,

145,

142,

141,

114, 113,

112, 109,

108, 107,

106, 105

BIOS ROM/Flash Address: During a BIOS ROM/Flash access, these

signals are used to drive the ROM/Flash address.

MWRN

BIOS ROM/Flash Write: During a BIOS ROM/Flash access, this signal is

used to enable data to be written to the Flash device.

MRDN

BIOS ROM/Flash Read: During a BIOS ROM/Flash access, this signal is

used to enable data to be read from the Flash device.

Media Independent Interface (MII) - and Gigabit Media Independent Interface (GMII).

Symbol

Pin No(s)

Direction

Description

DP83821 Datasheet(PDF) 6 Page - National Semiconductor (TI)

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