Mac network configuration register – Rainbow Electronics AT75C220 User Manual
Page 38
AT75C220
38
•
MPE
Management port enable. Set to one to enable the management port. When zero forces MDIO to high impedance
state.
•
CSR
Clear statistics registers. This bit is write-only. Writing a one clears the statistics registers.
•
ISR
Increment statistics registers. This bit is write-only. Writing a one increments all the statistics registers by one for test
purposes.
•
WES
Write enable for statistics registers. Setting this bit to one makes the statistics registers writable for functional test
purposes.
•
BP
Back pressure. If this field is set, then in half-duplex mode collisions are forced on all received frames by transmitting
64 bits of data (default pattern).
MAC Network Configuration Register
Register Name: ETH_CFG
Access Type: Read/write
Reset Value: 0x8
•
SPD
Speed. Set to 1 to indicate 100Mbit/sec. operation, 0 for 10Mbit/sec. Has no other functional effect.
•
FD
Full duplex. If set to 1, the transmit block ignores the state of collision and carrier sense and allows receive while
transmitting.
•
BR
Bit rate. Optional.
•
CAF
Copy all frames. When set to 1, all valid frames will be received.
•
NBC
No broadcast. When set to 1, frames addressed to the broadcast address of all ones will not be received.
•
MTI
Multicast hash enable, when set multicast frames will be received when six bits of the CRC of the destination address
point to a bit that is set in the hash register.
•
UNI
Unicast hash enable. When set, unicast frames will be received when six bits of the CRC of the destination address
point to a bit that is set in the hash register.
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
8
–
–
–
RTY
CLK
EAE
BIG
7
6
5
4
3
2
1
0
UNI
MTI
NBC
CAF
–
BR
FD
SPD