DP83865-EB National Semiconductor, DP83865-EB Datasheet - Page 21

• Manufacturer Part Number: DP83865-EB
• Description: BOARD EVALUATION DP83865
• Manufacturer: National Semiconductor

Specifications of DP83865-EB

• Main Purpose: Interface, Ethernet
• Utilized Ic / Part: DP83865
• Lead Free Status / RoHS Status: Not applicable / Not applicable

2.0 Register Block
2.3 Register Description
In the register description under the ‘Default’ heading, the following definitions hold true:
— RW
— RO
— LH
— LL
— SC
— P
— STRAP[x] = Default value read from Strapped value at device pin at Reset, where x may take the values:
Bit
15
14
13
12
= Read Write access
= Read Only access
= Latched High until read, based upon the occurrence of the corresponding event
= Latched Low until read, based upon the occurrence of the corresponding event
= Register sets on event occurrence (or is manually set) and Self-Clears when event ends
= Register bit is Permanently set to a default value
[0] internal pull-down
[1] internal pull-up
Bit Name
Loopback
Speed[0]
AN_EN
Reset
(Continued)
Table 3. Basic Mode Control Register (BMCR) address 0x00
STRAP[0], RW Speed Select:
STRAP[1], RW Auto-Negotiation Enable:
0, RW, SC
Default
0, RW
Reset:
1 = Initiate software Reset / Reset in Process.
0 = Normal operation.
This bit sets the status and control registers of the PHY to their
default states. This bit, which is self-clearing, returns a value of
one until the reset process is complete (approximately 1.2 ms for
reset duration). Reset is finished once the Auto-Negotiation pro-
cess has begun or the device has entered it’s forced mode.
Loopback:
1 = Loopback enabled.
0 = Normal operation.
The loopback function enables MII/GMII transmit data to be rout-
ed to the MII/GMII receive data path. The data loops around at
the DAC/ADC Subsystem (see block diagram page 2), bypassing
the Drivers/Receivers block. This exercises most of the PHY’s in-
ternal logic.
When Auto-Negotiation is disabled, bits 6 and 13 select device
speed selection per table below:
(The default value of this bit is = to the strap value of pin 7 during
reset/power-on IF Auto-Negotiation is disabled.)
1 = Auto-Negotiation Enabled - bits 6, 8 and 13 of this register are
ignored when this bit is set.
0 = Auto-Negotiation Disabled - bits 6, 8 and 13 determine the link
speed and mode.
(The default value of this bit is = to the strap value of pin 10 during
reset/power-on.)
Speed[1]
21
1
1
0
0
Speed[0]
1
0
1
0
Description
Speed Enabled
= Reserved
= 1000 Mbps
= 100 Mbps
= 10 Mbps
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