dp83261 National Semiconductor Corporation, dp83261 Datasheet - Page 79

• Manufacturer Part Number: dp83261
• Description: Bmac Device Fddi Media Access Controller
• Manufacturer: National Semiconductor Corporation

AFLAG
DAIG
FCSL
MFLAG
SAMESA
SAMEINFO
7 0 Signal Descriptions
7 3 2 3 PDU Flags
The PDU flags may be used with the received Frame Control field to determine if an attempt should be made to copy the frame
Symbol
Pin
56
54
53
60
61
63
I O
O
O
O
O
O
O
My Destination Address Recognized Indicates that an internal address match occurred on the
Destination Address field The internal address (MSA MLA GSA GLA) match is indicated by the
assertion of FCSL and DAIG AFLAG is asserted along with DARCVD It is reset when the next PDU
Starting Delimiter is received
Individual Group Address Flag Indicates the address type Valid on the first byte of the Destination
Address
Short Long Address Flag Indicates the size of the Destination Address Signal is valid when
FCRCVD is asserted
Used in conjunction with TKRCVD to indicate the type of token received
My Source Address Recognized Indicates that the received Source Address field matched the
MLA or MSA SA IG is ignored in the comparison MFLAG is asserted along with SARCVD It is reset
when the next PDU Starting Delimiter is received
Same Source Address Indicates three conditions
1 The Source Address of the current frame is the same as the Source Address of the previous frame
2 The current and previous frames were not MAC frames AND
3 The current and previous frames have the same address field size
SAMESA is asserted along with SARCVD It is reset when the next PDU starting delimiter is received
Same MAC Information Indicates two conditions
1 The first 4 bytes of the information field of the current frame are identical to the first 4 bytes of the
2 The current and previous non-Void frames were MAC frames
SAMEINFO is asserted along with INFORCVD It is reset when the next PDU Starting Delimiter is
received
Note that the FC field is not checked to insure that it is the same as in the previous frame This
includes the address size comparison
In REV1 of the BMAC Device Void frames are not ignored as stated in 1 and 2 above
0 Individual Address
1 Group Address
0 Short Address
1 Long Address
0 Non-restricted token
1 Restricted token
AND
previous non-Void frame AND
(Continued)
79
Description