AM79C978 Advanced Micro Devices, AM79C978 Datasheet - Page 189

• Manufacturer Part Number: AM79C978
• Description: Single-Chip 1/10 Mbps PCI Home Networking Controller
• Manufacturer: Advanced Micro Devices

TBR0: 10BASE-T PHY Control Register (Register 0)
Notes:
1. R/W = Read/Write, SC = Self Clearing, RO = Read only.
2. Soft Reset does not reset the PDX block. Refer to the Soft Reset Section for details.
3. Bits 8 and 13 have no effect if Auto-Negotiation is enabled (Bit 12 = 1).
4. If the ISOL pin of the chip and the Isolate bit in Register 0 is 1, this bit will be set.
Reg
0
0
0
0
0
0
0
0
0
0
Bits
6-0
15
14
13
12
11
10
9
8
7
Soft Reset (Note 2)
Auto-Negotiation
Speed Selection
Restart Auto-
Duplex Mode
Collision Test
Power Down
Negotiation
Loopback
Reserved
(Note 3)
(Note 4)
(Note 3)
Enable
Isolate
Name
Table 65. TBR0: 10BASE-T PHY Control Register (Register 0)
When write: 1 = PHY software reset,
0 = normal operation.
When read: 1 = reset in process,
0 = reset done.
0 = asserts Loopback mode,
1 = deasserts Loopback mode
1 = 100 Mbps,
0 = 10 Mbps
1 = enable Auto-Negotiation,
0 = disable Auto-Negotiation
1 = power down,
0 = normal operation
1 = electrically isolate PHY
0 = normal operation
1 = restart Auto-Negotiation,
0 = normal operation
1 = Full-Duplex,
0 = Half-Duplex
1 = enable COL signal test,
0 = disable COL signal test
Write as 0, ignore on read
Description
Am79C978
Read/Write
R/W, SC
R/W, SC
(Note 1)
R/W
R/W
R/W
R/W
R/W
R/W
R/W
RO
Default
Value
0
0
1
1
0
1
0
1
0
0
previous
Retains
Reset
value
Soft
0
0
1
1
0
1
0
0
0
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