CS89712-CB View Datasheet(PDF) - Cirrus Logic

Part Name

Description

MFG CO.

CS89712-CB

High-Performance, Low-Power System-on-Chip with 10BASE-T Ethernet Controller

Cirrus Logic 

CS89712

Function

Oscillators

Ethernet

EEPROM

10BASE-T

Interface

General

Ethernet Pins

No Connects

Signal

Name

MOSCIN

MOSCOUT

RTCIN

RTCOUT

EECS

Signal

Description

G9

I Main 3.6864 MHz oscillator for 18.432 MHz–73.728 MHz PLL

H9

O

R1

I Real-Time Clock 32.768 kHz oscillator

R2

O

A6

O EEPROM Chip Select - Active-high EEPROM select.

EESK

B6

O EEPROM Serial Clock - clocks data in/out of the EEPROM.

EEDataOut

A5

O EEPROM Data Out - used to send data to the EEPROM. Con-

nects to the DI pin on the EEPROM. When TEST is low, this

pin becomes the output for the Boundary Scan Test.

EEDataIn

B5

I EEPROM Data In - serial input used to receive data from the

EEPROM. Connects to the DO pin on the EEPROM.

EEDataIn is also used to sense the presence of the EEPROM.

This signal has a weak internal pullup.

TXD+/TXD- A16,

A15

O 10BASE-T Transmit, Differential Output Pair - drives 10 Mb/s

Manchester-encoded data to the 10BASE-T transmit pair.

RXD+/RXD- A12,

A11

I 10BASE-T Receive, Differential Input Pair - Differential input

pair receives 10 Mb/s Manchester-encoded data from the

10BASE-T receive pair.

RES

A10

I Reference Resistor, Input - This input should be connected

to a 4.99KW ± 1% resistor needed for biasing of internal ana-

log circuits.

XTAL[1:2] A8, A7

Crystal, Input/Output - A 20 MHz crystal should be con-

nected to these pins. If a crystal is not used, a 20 MHz signal

should connect to XTAL1 and XTAL2 should be left open.

LINKLED or B9

HC0

O Link Good LED or software Controlled Output 0, Open

Drain Output- When the HCE0 bit of the Self Control register

(Register 15) is clear, this active-low output is low when the

CS89712 detects the presence of valid link pulses. When the

HC0E bit is set, the software may drive this pin low by setting

the HCBO in the Self Control register.

LANLED

B8

O LAN Activity LED, Open Drain Output - During normal oper-

ation, this active-low output goes low for 6 ms whenever there

is a receive packet, a transmit packet, or a collision.

N/C

No connects should be left as no connects; do not connect to ground

Table 90. External Signal Functions (Continued)

Notes: 1. All deglitched inputs are via the 16.384 kHz clock. Each deglitched signal must be held active for at least

two clock periods. Therefore, the input signal must be active for at least ~125 µs to be detected cleanly.

2. The RTC crystal must be populated for the device to function properly.

144

DS502PP2

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