E F E c o n f i g u r a t i o n

Collision Window/Collision Retry register

Address: FF80 0410

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Reserved

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Reserved

 

 

 

CWIN

 

 

 

Reserved

 

 

RETX

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Register bit assignment

Bits

Access

Mnemonic

Reset

Description

 

 

 

 

 

D31:14

N/A

Reserved

N/A

N/A

 

 

 

 

 

D13:08

R/W

CWIN

’h37

Collision window

 

 

 

(55d)

A programmable field that represents the slot time

 

 

 

 

 

 

 

 

or collision window during which collisions occur in

 

 

 

 

properly configured networks. The collision

 

 

 

 

window starts at transmission, and includes the

 

 

 

 

preamble and start frame delimiter (SFD).

 

 

 

 

The default value for this field is ’h37 (55d), which

 

 

 

 

corresponds to the frame byte count at the end of

 

 

 

 

the window.

 

 

 

 

 

D07:04

N/A

Reserved

N/A

N/A

 

 

 

 

 

D03:00

R/W

RETX

’hF

Retransmission maximum

 

 

 

 

A programmable field that specifies the number of

 

 

 

 

retransmission attempts allowed after a collision,

 

 

 

 

before aborting the packet due to excessive

 

 

 

 

collisions.

The 802.3u standard specifies an attemptLimit of ’hF (15d).

Table 65: Collision Window/Collision Retry register bit definition

1 8 6

N S 7 5 2 0 H a r d w a r e R e f e r e n c e , R e v . D 0 3 / 2 0 0 6

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Image 200
Digi NS7520 manual Collision Window/Collision Retry register bit definition, Collision window, Retransmission maximum