DP83266 datasheet(77/152 Pages) NSC

77 / 152 page

70 Control Information (Continued)

Fixed Group Address MAP (FGM0 – FGM1)

If the first 44 bits of a long DA DA(47 – 4) or the first 12 bits of a short DA DA(15 – 4) are 1 the last 4 bits of the DA DA(3 – 0)

are used as an index into FGM

The 4-bit index into FGM can be viewed in two different ways It can be viewed as 4 bits selecting one of 16 bits where the

hexadecimal equivalent of DA(3 – 0) can be used as the index For example the broadcast address would index FGM(F)

Alternatively it can be viewed as one bit DA(3) selecting the byte (FGM0 or FGM1) and three bits DA(2 – 0) selecting one of 8

bits within a byte

Access Rules

Address

Read

Write

058–059h

Stop Mode

FGM0

FGM(7)

FGM(6)

FGM(5)

FGM(4)

FGM(3)

FGM(2)

FGM(1)

FGM(0)

FGM1

FGM(F)

FGM(E)

FGM(D)

FGM(C)

FGM(B)

FGM(A)

FGM(9)

FGM(8)

Bit FGM(F) must be set to One to ensure proper handling of frames with the UniversalBroadcast address including the SMT

NSA frames This is mandatory for interoperability on an FDDI Ring

Programmable Group Address MAP (PGM0 – PGM1F)

If the first 40 bits of a long DA DA(47 – 8) match the GLA or the first 8 bits of a short DA DA(15 – 8) match the GSA the last 8

bits of the DA are used as an index into PGM

The 8-bit index into PGM can be viewed in two different ways

1 As 8 bits selecting one of 256 bits where the hexadecimal equivalent of DA(7 – 0) can be used as the index For example a DA

with the last byte as A2h indexes PGM(A2)

2 As 5 bits DA(7 – 3) selecting the byte (PGM0 to PGM1F) and three bits DA(2 – 0) selecting one of 8 bits within a byte For

example a DA with the last byte of A2h (1010 0010b) selects PGM14 bit 2

It is possible to disable Long and Short Group Addressing by filling the Group Address Map with 0’s

In the MACSI device PGM(00) to PGM(7F) are set equal to PGM(80) to PGM(FF) and are accessible via the Control Interface

This implies that DA(7) of group addresses is a don’t care

Access Rules

Address

Read

Write

070–07Fh

Stop Mode

PGM0

PGM(7)

PGM(6)

PGM(5)

PGM(4)

PGM(3)

PGM(2)

PGM(1)

PGM(0)

PGM1

PGM(F)

PGM(E)

PGM(D)

PGM(C)

PGM(B)

PGM(A)

PGM(9)

PGM(8)

PGM2

PGM(17)

PGM(16)

PGM(15)

PGM(14)

PGM(13)

PGM(12)

PGM(11)

PGM(10)

PGM3

PGM(1F)

PGM(1E)

PGM(1D)

PGM(1C)

PGM(1B)

PGM(1A)

PGM(19)

PGM(18)

PGM4

PGM(27)

PGM(26)

PGM(25)

PGM(24)

PGM(23)

PGM(22)

PGM(21)

PGM(20)

PGM5

PGM(2F)

PGM(2E)

PGM(2D)

PGM(2C)

PGM(2B)

PGM(2A)

PGM(29)

PGM(28)

PGM6

PGM(37)

PGM(36)

PGM(35)

PGM(34)

PGM(33)

PGM(32)

PGM(31)

PGM(30)

PGM7

PGM(3F)

PGM(3E)

PGM(3D)

PGM(3C)

PGM(3B)

PGM(3A)

PGM(39)

PGM(38)

PGM8

PGM(47)

PGM(46)

PGM(45)

PGM(44)

PGM(43)

PGM(42)

PGM(41)

PGM(40)

PGM9

PGM(4F)

PGM(4E)

PGM(4D)

PGM(4C)

PGM(4B)

PGM(4A)

PGM(49)

PGM(48)

PGMA

PGM(57)

PGM(56)

PGM(55)

PGM(54)

PGM(53)

PGM(52)

PGM(51)

PGM(50)

PGMB

PGM(5F)

PGM(5E)

PGM(5D)

PGM(5C)

PGM(5B)

PGM(5A)

PGM(59)

PGM(58)

PGMC

PGM(67)

PGM(66)

PGM(65)

PGM(64)

PGM(63)

PGM(62)

PGM(61)

PGM(60)

PGMD

PGM(6F)

PGM(6E)

PGM(6D)

PGM(6C)

PGM(6B)

PGM(6A)

PGM(69)

PGM(68)

PGME

PGM(77)

PGM(76)

PGM(75)

PGM(74)

PGM(73)

PGM(72)

PGM(71)

PGM(70)

PGMF

PGM(7F)

PGM(7E)

PGM(7D)

PGM(7C)

PGM(7B)

PGM(7A)

PGM(79)

PGM(78)

DP83266 Datasheet(PDF) 77 Page - National Semiconductor (TI)

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