DP83266VF National Semiconductor, DP83266VF Datasheet - Page 54

• 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

Bit
D7
D6
D5
D4
7 0 Control Information
Option Register (Option)
The Ring Engine supports several options These options are typically static during operation but may be altered during
operation This register is initialized to Zero after a master reset
Access Rules
Register Bits
Address
ITC
001h
D7
Symbol
ITC
EMIND
IFCS
IRPT
EMIND
D6
Always
Read
Inhibit Token Capture When enabled the Ring Engine is prohibited from transmitting any (more) frames
This option prohibits entry to the Transmit Void and Data states from the Idle state and causes exit from the
Data state after the current frame has been transmitted
When enabled it is still possible to perform Immediate transmissions from the transmitter Claim and Beacon
states but not from the Data state
This option can be used to temporarily block normal data service It can also be used in conjunction with the
Inhibit Recovery Required option to permit access via the Control Interface to the MAC Parameter RAM during
MAC operation
External Matching Indicators Enables the setting of the transmitted A Indicator as an S symbol when the EA
pin is set This bit also enables the setting of the transmitted C Indicator as an S symbol when the internal
VCOPY signal is asserted by the System Interface and the A Indicator is set as a result of an external match
(i e the User asserts the EA pin) The Copied Not Copied Frame Counters also increment as a result of
external comparisons when this option is enabled
Implementer FCS Enables use of the standard CRC as the FCS on Implementer frames (FC FF
enabled Implementer frames are treated like all other frames When Implementer frames are received with
bad FCS and Er
On Implementer frames the Standard does not mandate the setting of the E Indicator on the result of the FCS
check This allows Implementers to use alternate Frame Check Sequences aside from the standard 32-bit
CRC Implementers may also choose not to use any FCS in applications such as packet voice
If other stations in the ring are using Implementer frames with a non-standard FCS this option may cause an
interoperability problem
Inhibit Repeat When enabled
1 the Ring Engine cannot enter the Transmitter Repeat and Issue Token states This causes all received
2 Void frames are not transmitted during a service opportunity
3 Idle to Repeat transition is inhibited and all received tokens and MAC frames except Lower Claim and
When the ring is operational enabling this option causes the Reset actions to occur upon the completion of
the service opportunity if any When the ring is not operational Immediate Requests are serviced and
continue to completion
The Inhibit Repeat option can be used to scrub the ring for a period longer than the Ring Latency The option is
also useful in non-FDDI applications to allow full duplex communication
PDUs to be stripped and prevents tokens from being issued
My Beacon frames are ignored (Lower Claim and My Beacon frames may be ignored by setting
Option IRR)
IFCS
D5
Always
Write
e
R the E Indicator is transmitted as S and EICT is incremented
IRPT
(Continued)
D4
IRR
D3
54
ITR
D2
Description
ELA
D1
ESA
D0
e
10) When