E t h e r n e t M o d u l e

Maximum Frame register

Address: FF80 0414

Register bit assignment

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

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

MAXF

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Bits

Access

Mnemonic

Reset

Description

 

 

 

 

 

D31:16

N/A

Reserved

N/A

N/A

 

 

 

 

 

D15:00

R/W

MAXF

’h

Maximum frame length

0600

Represents a maximum receive frame of 1536

 

 

octets (resets to ’h0600). An untagged maximum

 

size Ethernet is 1518 octets. A tagged frame adds

 

four octets, for a total of 1522 octets.

 

Program this field if you want a shorter maximum

 

length restriction.

 

Note: If a proprietary header is allowed, adjust

 

this field accordingly. For example, if

 

4-byte headers are appended to frames,

 

the MAXF field should be set to 1526

 

octets. This setting allows the maximum

 

VLAN tagged frame plus the 4-byte

 

header.

 

 

Table 66: Maximum Frame register bit definition

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Digi NS7520 manual Maximum Frame register bit definition, Maximum frame length