DP83266VF National Semiconductor, DP83266VF Datasheet - Page 23

• Manufacturer Part Number: DP83266VF
• Description: IC MEDIA ACSS CTRL INTF 160PQFP
• Manufacturer: National Semiconductor

Specifications of DP83266VF

• Applications: *
• Voltage - Supply: 4.75 V ~ 5.25 V
• Package / Case: 160-BFQFP
• Mounting Type: Surface Mount
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Interface: -
• Other names: *DP83266VF

5 0 Functional Description (Ring Engine)
Note 1 Synchronous Requests are not serviced when RELR BCNR
Note 2 Restricted Requests are not serviced when RELR MACR
Note 3 Restricted Dialogues only begin when a Non-Restricted token has been received and transmitted
Note 4 Immediate Requests are serviced when the ring is Non-Operational These requests are serviced from the Data state if neither signal RQCLM nor RQBCN
is asserted If signal RQCLM is asserted Immediate Requests are serviced from the Claim State If signal RQBCN is asserted Immediate Requests are serviced
from the Beacon State RQCLM and RQBCN do not cause transitions to the Claim and Beacon States
On Transmit frames are checked to see that they are of a
minimum length If the end of a frame is reached before a
valid length is transmitted the frame will be aborted and a
Void frame will be transmitted (as with all aborted frames) A
MAC frame with a zero length INFO field will not be aborted
even though the Receiver will not recognize it as a valid
frame Frame lengths are not checked for the maximum al-
lowable length (4500 bytes)
Also on the Transmit side the L bit in the FC field is
checked against the ESA and ELA bits in the Option Regis-
Void
MAC
non-MAC
RQRCLS
Frame
Types
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
TABLE 5-4 Valid Frame Length
Address
(minimum number
Short
13
9
9
of bytes)
Reserved
Reserved
RbeginD
Apri 1
RendD
AsynD
Name
Async
RcntD
ImmN
ImmR
None
Rbeg
Rend
Sync
Rcnt
Imm
Address
Long
17
21
17
including a 4 byte
INFO field
including a 0 byte
INFO field
Immediate
Immediate
Immediate
Restricted
Restricted
Restricted
Restricted
Restricted
Restricted
Reserved
Reserved
THSH1
Class
Async
Async
Async
TABLE 5-3 Request Service Classes
None
Sync
Notes
e
e
1
1
disabled
disabled
disabled
disabled
disabled
disabled
disabled
disabled
23
enabled
enabled
enabled
enabled
enabled
THT
ter (if the SA Transparency option is not selected) to insure
that a frame of that address length can be transmitted If the
selected address length is not enabled the frame is aborted
at the beginning of the SA field If SA Transparency is se-
lected the frame is not aborted
When Option IRPT is set and SAT and SAIGT are selected
or when Mode DIAG is set the minimum frame length is one
data byte
5 5 FRAME STATUS PROCESSING
Each frame contains three or more Control Indicators The
FDDI Standard specifies three the E A and C Indicators
When a frame is transmitted the Control Indicators are
transmitted as R (Reset) symbols If an error is detected by
a station that receives the frame the E Indicator is changed
to an S (Set) symbol If a station recognizes the DA of a
frame as its own address (Individual Group or Broadcast)
the A Indicator is changed to an S symbol If that station
then copies the frame the C Indicator is changed to an S
symbol
The received value of the Control Indicators for every frame
received is reported at the MAC Indicate Interface on sig-
nals MID(7 – 0) On a frame transmitted by this station the
returning Control Indicators give the transmission status
(Continued)
Capture
non-rstr
non-rstr
non-rstr
non-rstr
non-rstr
Token
none
none
none
any
rstr
rstr
rstr
rstr
captured
non-rstr
non-rstr
non-rstr
non-rstr
non-rstr
non-rstr
Token
Issue
none
rstr
rstr
rstr
rstr
rstr
Notes
2 3
2 3
1
4
4
4
2
2
2
2