200
Am79C973/Am79C975
P R E L I M I N A R Y
ANR16: INTERRUPT Status and Enable Register (Register 16)
The Interrupt bits indicate when there is a change in the
Link Status, Duplex Mode, Auto-Negotiation status, or
Speed status. Register 16 contains the interrupt status
and interrupt enable bits. The status is always updated
whether or not the interrupt enable bits are set. When
an interrupt occurs, the system will need to read the in-
terrupt register to clear the status bits and determine
the course of action needed. See Table 49.
Table 49. ANR16: INTERRUPT Status and Enable Register (Register 16)
Note:
1. All bits, except bit 13, are cleared on read (COR). The register must be read twice to see if it has been cleared.
ANR17: PHY Control/Status Register (Register 17)
This register is used to control the configuration of the
10/100 PHY unit of the Am79C973/Am79C975 device.
See Table 50.
When configuring the device to
enable/disable the
scrambler/descrambler (SDISSCR), and/or to enable/
disable the alignment (SDISALIGN), a software reset
after a write operation to the appropriate bits in this reg-
ister is mandatory for proper configuration. If a register
bit is only appropriate to use at one speed, then the
speed will be indicated in parenthesis in the Name col-
umn, for example, (10M).
Bit(s)
Name
Description
Read/
Write
H/W or Soft
Reset
15:14
Reserved
RO
0
13
Interrupt Test Enable
(Note 1)
1 = When this bit is set, setting bits 12:9 of this register
will cause an INTR condition and will set bits 4:1
accordingly. The effect is to test the register bits with
a forced interrupt condition.
0 = Bits 4:1 are only set if the interrupt condition (if any
bits in 12:9 are set) occurs.
R/W
0
12
Link Status Change
Interrupt Enable
1 = Link Status Change
0 = This interrupt is masked.
R/W
0
11
Duplex Mode Change
Interrupt Enable
1 = Duplex Mode Change
0 = This interrupt is masked.
R/W
0
10
Auto-Neg Change
Interrupt Enable
1 = Auto-Neg Change
0 = This interrupt is masked.
R/W
0
9
Speed Change
Interrupt Enable
1 = Speed Change
0 = This interrupt is masked.
R/W
0
8
Global
Interrupt Enable
1= Global Interrupt
0 = This interrupt is masked.
R/W
0
7:5
Reserved
RO
0
4
Link Status Change
Interrupt
1 = Link Status has changed on a port.
0 = No change in Link Status
RO,
LH
0
3
Duplex Mode Change
Interrupt
1 = Duplex Mode has changed on a port
0 = No change in Duplex mode
RO,
LH
0
2
Auto-Neg Change
Interrupt
1 = Auto-Neg status has changed on a port
0 = No change in Auto-Neg status
RO,
LH
0
1
Speed Change
Interrupt
1 = Speed status has changed on a port
0 = No change
RO,
LH
0
0
Global
Interrupt
1 = Indicates a change in status of any of the above
interrupts
0 = Indicates no change in Interrupt Status
RO,
LH
0