LAN8740A Datasheet, PDF (60/136 Pages) Microchip Technology – Small Footprint MII/RMII 10/100 Energy Efficient Ethernet Transceiver with HP Auto-MDIX and flexPWR® Technology

LAN8740A/LAN8740Ai
4.2.1 BASIC CONTROL REGISTER
Index (In Decimal): 0
Size:
16 bits
Bits
Description
Type
Default
15 Soft Reset
R/W
1 = Software reset. Bit is self-clearing. When setting this bit do not set other
SC
bits in this register.
Note:
The configuration (as described in Section 3.7.2, "MODE[2:0]:
Mode Configuration") is set from the register bit values, and not
from the mode pins.
14 Loopback
R/W
0 = Normal operation
1 = Loopback mode
13 Speed Select
R/W
0 = 10 Mbps
1 = 100 Mbps
0b
0b
(see Note 1)
Note: Ignored if auto-negotiation is enabled (0.12 = 1).
12 Auto-Negotiation Enable
0 = Disable auto-negotiate process
1 = Enable auto-negotiate process (overrides 0.13 and 0.8)
11 Power Down
0 = Normal operation
1 = General power down mode
10 Isolate
0 = Normal operation
1 = Electrical isolation of PHY from the MII/RMII
9 Restart Auto-Negotiate
0 = Normal operation
1 = Restart auto-negotiate process
Note: Bit is self-clearing.
8 Duplex Mode
0 = Half duplex
1 = Full duplex
R/W (see Note 1)
R/W
0b
R/W
0b
R/W
0b
SC
R/W (see Note 1)
Note: Ignored if Auto-Negotiation is enabled (0.12 = 1).
7 Collision Test
0 = Disable COL test
1 = Enable COL test
6:0 RESERVED
R/W
0b
RO
-
Note 1: The default value of this bit is determined by the MODE[2:0] configuration straps. Refer to Section 3.7.2,
"MODE[2:0]: Mode Configuration" for additional information.
DS00001987A-page 60
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