com20020-5 Standard Microsystems Corp., com20020-5 Datasheet - Page 7

• Manufacturer Part Number: com20020-5
• Description: Com20020-5 Ulanc Universal Local Area Network Controller With 2k X 8 On-board Ram
• Manufacturer: Standard Microsystems Corp.

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ID refers to the identification number of the ID assigned to this node.
NID refers to the next identification number that receives the token after
after this ID passes it.
SID refers to the source identification.
DID refers to the destination identification.
SOH refers to the start of header character; preceeds all data packets.
N
Reconfiguration
Timer (420 mS)
N
Broadcast?
Start
Was Packet
Broadcast?
TA?
Packet
Send
Activity
ACK?
37.35
us?
No
for
Y
N
N
Reconfigure
Timer has
Timed Out
Y
Y
Y
N
Y
Set TMA
Transmit
Transmit
Set TA
NAK
ACK
Y
FIGURE 1 - COM20020-5 OPERATION
to Transmit to
Reconfigure
RAM Buffer
Write ID to
Set NID=ID
Invitation
Read Node ID
Power On
this ID?
Y
Send
Burst
Increment
Free Buffer
RI?
Transmit
Enquiry
NID
Y
Y
ACK?
N
Y
Free Buffer
Enquiry to
N
N
this ID?
NAK?
Y
N
Activity
37.35
Activity
37.35
No
for
us?
us?
No
N
for
7
1
N
Y
Set TA
N
Pass the
Y
Token
RI?
SEND ACK
Write Buffer
with Packet
Y
LENGTH
Write SID
to Buffer
N
DID
=0?
CRC
N
=ID?
Y
OK?
Y
=ID?
OK?
SOH?
DID
DID
=0?
1
DID
N
Y
Y
N
Y
Y
N
N
N
N
Broadcast
Enabled?
Y
Set RI
N
N
Start Timer:
T=(255-ID)
Set NID=ID
No Activity
x 73 us
On Line?
Activity
for 41
T=0?
uS?
Y
Y
N
Y
N