CS89712 datasheet(46/170 Pages) CIRRUS

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CS89712

DS502PP2

2.24.4

Writing and Erasing the EEPROM

To write data to the EEPROM, the software must

execute the following series of commands:

1) Issue an Erase/Write Enable command.

2) Load the data into the EEPROM Data register.

3) Issue a Write command.

4) Issue an Erase/Write Disable command.

During the Erase command, the Ethernet port

writes FFh to the specified EEPROM location.

During the Erase-All command, the Ethernet port

writes FFh to all locations.

2.25 Ethernet LEDs

The Ethernet port provides three output pins that

can be used to control LEDs or external logic.

2.25.1

LANLED

LANLED goes low whenever the Ethernet port

transmits or receives a frame, or when it detects a

collision. LANLED remains low until there has

been no activity for 6 ms (i.e. each transmission, re-

ception, or collision produces a pulse lasting a min-

imum of 6 ms).

2.25.2

LINKLED or HC0

LINKLED or HC0 can be controlled by either the

Ethernet port or the software. When controlled by

the Ethernet port, LINKLED is low whenever the

Ethernet port receives valid 10BASE-T link pulses.

To configure this pin for software control, the

HC0E bit (SelfCTL register, Bit C) must be clear.

When controlled by the software, LINKLED is low

when the HCB0 bit (SelfCTL register, Bit E) is set.

To configure it for software control, the HC0E bit

must be set. Table 27 summarizes this operation.

Command

Opcode

(bits 9,8)

EEPROM Address

(bits 7 to 0)

Data

EEPROM Type

Execution

Time

Read Register

1,0

word address

yes

all

25 µs

Write Register

0,1

word address

yes

all

10 ms

Erase Register

1.1

word address

all

10 ms

Erase/Write Enable

0,0

XX11-XXXX

‘CS46, ‘C46

9 µs

11XX-XXXX

‘CS56, ‘C56, ‘CS66, ‘C66

9 µs

Erase/Write Disable

0,0

XX00-XXXX

‘CS46, ‘C46

9 µs

00XX-XXXX

‘CS56, ‘C56, ‘CS66, ‘C66

9 µs

Erase-All Registers

0,0

XX10-XXXX

‘CS46, ‘C46

10 ms

10XX-XXXX

‘CS56, ‘C56, ‘CS66, ‘C66

9 µs

Write-All Register

0,0

XX01-XXXX

yes

‘CS46, ‘C46

10 ms

01XX-XXXX

yes

‘CS56, ‘C56, ‘CS66, ‘C66

10 ms

Table 26. EEPROM Commands

HC0E

(Bit C)

HCB0

(Bit E)

Pin Function

0N/A

Pin configured as LINKLED:

Output is low when valid

10BASE-T link pulses are

detected. Output is high if valid

link pulses are not detected

Pin configured as HC0:

Output is high

Pin configured as HC0:

Output is low

Table 27. LINKLED/HC0 Pin Operation

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