March 2006
17
M9999-030106
KS8721B/BT
Micrel, Inc.
Register Map
Register No.
Description
0h
Basic Control Register
1h
Basic Status Register
2h
PHY Identier I
3h
PHY Identier II
4h
Auto-Negotiation Advertisement Register
5h
Auto-Negotiation Link Partner Ability Register
6h
Auto-Negotiation Expansion Register
7h
Auto-Negotiation Next Page Register
8h
Link Partner Next Page Ability
15h
RXER Counter Register
1bh
Interrupt Control/Status Register
1fh
100BaseTX PHY Control Register
Address
Name
Description
Mode(Note 1)
Default
Register 0h - Basic Control
0.15
Reset
1 = software reset. Bit is self-clearing
RW/SC
0
0.14
Loop-back
1 = loop-back mode; 0 = normal operation
RW
0
0.13
Speed Select (LSB)
1 = 100Mbps; 0 = 10Mbps
RW
Set by
Ignored if Auto-Negotiation is enabled (0.12 = 1)
SPD100
0.12
Auto-Negotiation Enable
1 = enable auto-negotiation process (override 0.13 and 0.8) RW
Set by
0 = disable auto-negotiation process
NWAYEN
0.11
Power Down
1 = power down mode; 0 = normal operation
RW
0
0.10
Isolate
1 = electrical isolation of PHY from MII and TX+/TX-
RW
Set by ISO
0 = normal operation
0.9
Restart Auto-Negotiation
1 = restart auto-negotiation process
RW/SC
0
0 = normal operation. Bit is self-clearing
0.8
Duplex Mode
1 = full duplex; 0 = half duplex
RW
Set by
DUPLEX
0.7
Collision Test
1 = enable COL test; 0 = disable COL test
RW
0
0.6:1
Reserved
RO
0
0.0
Disable
0 = enable transmitter
R/W
0
Transmitter
1 = disable transmitter
Register 1h - Basic Status
1.15
100BaseT4
1 = T4 capable; 0 = not T4 capable
RO
0
1.14
100BaseTX Full Duplex
1 = capable of 100BaseX full duplex
RO
1
0 = not capable of 100BaseX full duplex
1.13
100BaseTX Half Duplex
1 = capable of 100BaseX half duplex
RO
1
0 = not capable of 100BaseX half duplex
1.12
10BaseT Full Duplex
1 = 10Mbps with full duplex
RO
1
0 = no 10Mbps with full duplex capability
1.11
10BaseT Half Duplex
1 = 10Mbps with half duplex
RO
1
0 = no 10Mbps with half duplex capability
Note 1. RW: Read/Write, RO: Read only, SC: Self clear, LH: Latch High, LL: Latch Low. Some of the default values are set by strap-in. See “Srap-
ping Options.”
Register 0h - Basic Control
0.15
Reset
1 = software reset. Bit is self-clearing
RW/SC
0
0.14
Loop-back
1 = loop-back mode; 0 = normal operation
RW
0
0.13
Speed Select (LSB)
1 = 100Mbps; 0 = 10Mbps
RW
Set by
Ignored if Auto-Negotiation is enabled (0.12 = 1)
SPD100
0.12
Auto-Negotiation Enable
1 = enable auto-negotiation process (override 0.13 and 0.8) RW
Set by
0 = disable auto-negotiation process
NWAYEN
0.10
Isolate
1 = electrical isolation of PHY from MII and TX+/TX-
RW
Set by ISO
0 = normal operation
0.9
Restart Auto-Negotiation
1 = restart auto-negotiation process
RW/SC
0
0 = normal operation. Bit is self-clearing
0.8
Duplex Mode
1 = full duplex; 0 = half duplex
RW
Set by
DUPLEX
0.7
Collision Test
1 = enable COL test; 0 = disable COL test
RW
0
0.6:1
Reserved
RO
0
0.0
Disable
0 = enable transmitter
R/W
0
Transmitter
1 = disable transmitter
Register 1h - Basic Status
1.15
100BaseT4
1 = T4 capable; 0 = not T4 capable
RO
0
1.14
100BaseTX Full Duplex
1 = capable of 100BaseX full duplex
RO
1
0 = not capable of 100BaseX full duplex
1.13
100BaseTX Half Duplex
1 = capable of 100BaseX half duplex
RO
1
0 = not capable of 100BaseX half duplex
1.12
10BaseT Full Duplex
1 = 10Mbps with full duplex
RO
1
0 = no 10Mbps with full duplex capability
1.11
10BaseT Half Duplex
1 = 10Mbps with half duplex
RO
1
0 = no 10Mbps with half duplex capability
0h
Basic Control Register
1h
Basic Status Register
2h
PHY Identier I
3h
PHY Identier II
4h
Auto-Negotiation Advertisement Register
5h
Auto-Negotiation Link Partner Ability Register
6h
Auto-Negotiation Expansion Register
7h
Auto-Negotiation Next Page Register
8h
Link Partner Next Page Ability
15h
RXER Counter Register
1bh
Interrupt Control/Status Register
1fh
100BaseTX PHY Control Register
Register No.
Description
0h
Basic Control Register
1h
Basic Status Register
2h
PHY Identier I
3h
PHY Identier II
4h
Auto-Negotiation Advertisement Register
5h
Auto-Negotiation Link Partner Ability Register
6h
Auto-Negotiation Expansion Register
7h
Auto-Negotiation Next Page Register
8h
Link Partner Next Page Ability
15h
RXER Counter Register
1bh
Interrupt Control/Status Register
1fh
100BaseTX PHY Control Register
Address
Name
Description
Mode
Default
Address
Name
Description
Mode
0.15
Reset
1 = software reset. Bit is self-clearing
RW/SC
0
0.14
Loop-back
1 = loop-back mode; 0 = normal operation
RW
0
0.13
Speed Select (LSB)
1 = 100Mbps; 0 = 10Mbps
RW
Set by
Ignored if Auto-Negotiation is enabled (0.12 = 1)
SPD100
0.12
Auto-Negotiation Enable
1 = enable auto-negotiation process (override 0.13 and 0.8) RW
Set by
0 = disable auto-negotiation process
NWAYEN
0.11
Power Down
1 = power down mode; 0 = normal operation
RW
0
0.10
Isolate
1 = electrical isolation of PHY from MII and TX+/TX-
RW
Set by ISO
0 = normal operation
0.9
Restart Auto-Negotiation
1 = restart auto-negotiation process
RW/SC
0
0 = normal operation. Bit is self-clearing
0.8
Duplex Mode
1 = full duplex; 0 = half duplex
RW
Set by
DUPLEX
0.7
Collision Test
1 = enable COL test; 0 = disable COL test
RW
0
0.6:1
Reserved
RO
0
0.0
Disable
0 = enable transmitter
R/W
0
Transmitter
1 = disable transmitter
0.15
Reset
1 = software reset. Bit is self-clearing
RW/SC
0
0.14
Loop-back
1 = loop-back mode; 0 = normal operation
RW
0
0.13
Speed Select (LSB)
1 = 100Mbps; 0 = 10Mbps
RW
Set by
Ignored if Auto-Negotiation is enabled (0.12 = 1)
SPD100
0.12
Auto-Negotiation Enable
1 = enable auto-negotiation process (override 0.13 and 0.8) RW
Set by
0 = disable auto-negotiation process
NWAYEN
0.11
Power Down
1 = power down mode; 0 = normal operation
RW
0
0.10
Isolate
1 = electrical isolation of PHY from MII and TX+/TX-
RW
Set by ISO
0.9
Restart Auto-Negotiation
1 = restart auto-negotiation process
RW/SC
0
0 = normal operation. Bit is self-clearing
0.8
Duplex Mode
1 = full duplex; 0 = half duplex
RW
Set by
DUPLEX
0.7
Collision Test
1 = enable COL test; 0 = disable COL test
RW
0
0.6:1
Reserved
RO
0
0.0
Disable
0 = enable transmitter
R/W
0
0.15
Reset
1 = software reset. Bit is self-clearing
RW/SC
0
0.14
Loop-back
1 = loop-back mode; 0 = normal operation
RW
0
0.13
Speed Select (LSB)
1 = 100Mbps; 0 = 10Mbps
RW
Set by
Ignored if Auto-Negotiation is enabled (0.12 = 1)
SPD100
0.12
Auto-Negotiation Enable
1 = enable auto-negotiation process (override 0.13 and 0.8) RW
Set by
0 = disable auto-negotiation process
NWAYEN
0.11
Power Down
1 = power down mode; 0 = normal operation
RW
0
0.10
Isolate
1 = electrical isolation of PHY from MII and TX+/TX-
RW
Set by ISO
0 = normal operation
0.9
Restart Auto-Negotiation
1 = restart auto-negotiation process
RW/SC
0
0 = normal operation. Bit is self-clearing
0.8
Duplex Mode
1 = full duplex; 0 = half duplex
RW
Set by
DUPLEX
0.7
Collision Test
1 = enable COL test; 0 = disable COL test
RW
0
0.6:1
Reserved
RO
0
0.0
Disable
0 = enable transmitter
R/W
0
Transmitter
1 = disable transmitter
0.15
Reset
1 = software reset. Bit is self-clearing
RW/SC
0
0.14
Loop-back
1 = loop-back mode; 0 = normal operation
RW
0
0.13
Speed Select (LSB)
1 = 100Mbps; 0 = 10Mbps
RW
Set by
Ignored if Auto-Negotiation is enabled (0.12 = 1)
SPD100
0.12
Auto-Negotiation Enable
1 = enable auto-negotiation process (override 0.13 and 0.8) RW
Set by
0 = disable auto-negotiation process
NWAYEN
0.11
Power Down
1 = power down mode; 0 = normal operation
RW
0
0.10
Isolate
1 = electrical isolation of PHY from MII and TX+/TX-
RW
Set by ISO
0.9
Restart Auto-Negotiation
1 = restart auto-negotiation process
RW/SC
0
0.8
Duplex Mode
1 = full duplex; 0 = half duplex
RW
Set by
DUPLEX
0.7
Collision Test
1 = enable COL test; 0 = disable COL test
RW
0
0.6:1
Reserved
RO
0
0.0
Disable
0 = enable transmitter
R/W
0
1.15
100BaseT4
1 = T4 capable; 0 = not T4 capable
RO
0
1.14
100BaseTX Full Duplex
1 = capable of 100BaseX full duplex
RO
1
0 = not capable of 100BaseX full duplex
1.13
100BaseTX Half Duplex
1 = capable of 100BaseX half duplex
RO
1
0 = not capable of 100BaseX half duplex
1.12
10BaseT Full Duplex
1 = 10Mbps with full duplex
RO
1
0 = no 10Mbps with full duplex capability
1.11
10BaseT Half Duplex
1 = 10Mbps with half duplex
RO
1
0 = no 10Mbps with half duplex capability
1.15
100BaseT4
1 = T4 capable; 0 = not T4 capable
RO
0
1.14
100BaseTX Full Duplex
1 = capable of 100BaseX full duplex
RO
1
1.13
100BaseTX Half Duplex
1 = capable of 100BaseX half duplex
RO
1
1.12
10BaseT Full Duplex
1 = 10Mbps with full duplex
RO
1
1.11
10BaseT Half Duplex
1 = 10Mbps with half duplex
RO
1
1.15
100BaseT4
1 = T4 capable; 0 = not T4 capable
RO
0
1.14
100BaseTX Full Duplex
1 = capable of 100BaseX full duplex
RO
1
0 = not capable of 100BaseX full duplex
1.13
100BaseTX Half Duplex
1 = capable of 100BaseX half duplex
RO
1
0 = not capable of 100BaseX half duplex
1.12
10BaseT Full Duplex
1 = 10Mbps with full duplex
RO
1
0 = no 10Mbps with full duplex capability
1.11
10BaseT Half Duplex
1 = 10Mbps with half duplex
RO
1
0 = no 10Mbps with half duplex capability
1.15
100BaseT4
1 = T4 capable; 0 = not T4 capable
RO
0
1.14
100BaseTX Full Duplex
1 = capable of 100BaseX full duplex
RO
1
1.13
100BaseTX Half Duplex
1 = capable of 100BaseX half duplex
RO
1
1.12
10BaseT Full Duplex
1 = 10Mbps with full duplex
RO
1
1.11
10BaseT Half Duplex
1 = 10Mbps with half duplex
RO
1