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46 isochronous receive context match register – Texas Instruments Dual/Single Socket CardBus and UntraMedia Controller PCI7621 User Manual

Page 224

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8−44

8.46 Isochronous Receive Context Match Register

The isochronous receive context match register starts an isochronous receive context running on a specified cycle
number, filters incoming isochronous packets based on tag values, and waits for packets with a specified sync value.
The n value in the following register addresses indicates the context number (n = 0, 1, 2, 3). See Table 8−35 for a
complete description of the register contents.

Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

Name

Isochronous receive context match

Type

RW

RW

RW

RW

R

RW

RW

RW

RW

RW

RW

RW

RW

RW

RW

RW

Default

X

X

X

X

0

0

0

X

X

X

X

X

X

X

X

X

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

Name

Isochronous receive context match

Type

RW

RW

RW

RW

RW

RW

RW

RW

R

RW

RW

RW

RW

RW

RW

RW

Default

X

X

X

X

X

X

X

X

0

X

X

X

X

X

X

X

Register:

Isochronous receive context match

Offset:

410Ch + (32 * n)

Type:

Read/Write, Read-only

Default:

XXXX XXXXh

Table 8−35. Isochronous Receive Context Match Register Description

BIT

FIELD NAME

TYPE

DESCRIPTION

31

tag3

RW

If bit 31 is set to 1, this context matches on isochronous receive packets with a tag field of 11b.

30

tag2

RW

If bit 30 is set to 1, this context matches on isochronous receive packets with a tag field of 10b.

29

tag1

RW

If bit 29 is set to 1, this context matches on isochronous receive packets with a tag field of 01b.

28

tag0

RW

If bit 28 is set to 1, this context matches on isochronous receive packets with a tag field of 00b.

27

RSVD

R

Reserved. Bit 27 returns 0 when read.

26−12

cycleMatch

RW

This field contains a 15-bit value corresponding to the two low-order bits of cycleSeconds and the 13-bit
cycleCount field in the cycleStart packet. If cycleMatchEnable (bit 29) in the isochronous receive
context control register (see Section 8.44) is set to 1, then this context is enabled for receives when
the two low-order bits of the isochronous cycle timer register at OHCI offset F0h (see Section 8.34)
cycleSeconds field (bits 31−25) and cycleCount field (bits 24−12) value equal this field (cycleMatch)
value.

11−8

sync

RW

This 4-bit field is compared to the sync field of each isochronous packet for this channel when the
command descriptor w field is set to 11b.

7

RSVD

R

Reserved. Bit 7 returns 0 when read.

6

tag1SyncFilter

RW

If bit 6 and bit 29 (tag1) are set to 1, then packets with tag 01b are accepted into the context if the two
most significant bits of the packet sync field are 00b. Packets with tag values other than 01b are filtered
according to bit 28 (tag0), bit 30 (tag2), and bit 31 (tag3) without any additional restrictions.

If this bit is cleared, then this context matches on isochronous receive packets as specified in
bits 28−31 (tag0−tag3) with no additional restrictions.

5−0

channelNumber

RW

This 6-bit field indicates the isochronous channel number for which this isochronous receive DMA
context accepts packets.