LAN8700 datasheet(41/74 Pages) MICROCHIP

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DS00002260A-page 41

LAN8700/LAN8700i

bit To set an interrupt, set the corresponding mask bit in the interrupt Mask register 30 (see Table 5-46). Then when the

event to assert nINT is true, the nINT output will be asserted.

When the corresponding Event to De-Assert nINT is true, then the nINT will be de-asserted.

Note 5-2

If the mask bit is enabled and nINT has been de-asserted while ENERGYON is still high, nINT will

assert for 256 ms, approximately one second after ENERGYON goes low when the Cable is

unplugged. To prevent an unexpected assertion of nINT, the ENERGYON interrupt mask should

always be cleared as part of the ENERGYON interrupt service routine

5.3.2

ALTERNATE INTERRUPT SYSTEM

The Alternative method is enabled by writing a ‘1’ to 17.6 (ALTINT).

To set an interrupt, set the corresponding bit of the in the Mask Register 30, (see Table 5-47).

To Clear an interrupt, either clear the corresponding bit in the Mask Register (30), this will de-assert the nINT output, or

Clear the Interrupt Source, and write a ‘1’ to the corresponding Interrupt Source Flag. Writing a ‘1’ to the Interrupt Source

Flag will cause the state machine to check the Interrupt Source to determine if the Interrupt Source Flag should clear or

stay as a ‘1’. If the Condition to De-Assert is true, then the Interrupt Source Flag is cleared, and the nINT is also de-

asserted. If the Condition to De-Assert is false, then the Interrupt Source Flag remains set, and the nINT remains

asserted.

For example 30.7 is set to ‘1’ to enable the ENERGYON interrupt. After a cable is plugged in, ENERGYON (17.1) goes

active and nINT will be asserted low.

To de-assert the nINT interrupt output, either.

Clear the ENERGYON bit (17.1), by removing the cable, then writing a ‘1’ to register 29.7.

- Or -

Clear the Mask bit 30.1 by writing a ‘0’ to 30.1.

TABLE 5-46:

INTERRUPT MANAGEMENT

Mask

Interrupt Source Flag

Interrupt Source

Event to Assert nINT

Event to De-Assert nINT

30.7

29.7

ENERGYON

17.1

ENERGYON

Rising 17.1(5-2)

Falling 17.1 or

Reading register 29

30.6

29.6

Auto-Negotiation

complete

1.5

Auto-Negotiate

Complete

Rising 1.5

Falling 1.5 or

Reading register 29

30.5

29.5

Remote Fault Detected

1.4

Remote Fault

Rising 1.4

Falling 1.4, or

Reading register 1 or

Reading register 29

30.4

29.4

Link Down

1.2

Link Status

Falling 1.2

Reading register 1 or

Reading register 29

30.3

29.3

Auto-Negotiation LP

Acknowledge

5.14

Acknowledge

Rising 5.14

Falling 5.14 or

Read register 29

30.2

29.2

Parallel Detection Fault

6.4

Parallel Detection Fault

Rising 6.4

Falling 6.4 or

Reading register 6, or

Reading register 29 or

Re-Auto Negotiate or

Link down

30.1

29.1

Auto-Negotiation Page

Received

6.1

Page Received

Rising 6.1

Falling of 6.1 or

Reading register 6, or

Reading register 29

Re-Auto Negotiate, or

Link Down.

Note:

The ENERGYON bit 17.1 is defaulted to a ‘1’ at the start of the signal acquisition process, therefore the

Interrupt source flag 29.7 will also read as a ‘1’ at power-up. If no signal is present, then both 17.1 and 29.7

will clear within a few milliseconds.

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