Power On
Reconfigure
Timer has
Timed Out
Send
Reconfigure
Burst
Read Node ID
Write ID to
RAM Buffer
1
Set NID=ID
Start
Reconfiguration
Timer (420 mS)*
Y
Invitation
to Transmit to
this ID?
N
N
TA?
Y
Y
Free Buffer
Enquiry to
this ID?
N
N
Y
Y
N
Write SID
to Buffer
N
Transmit
NAK
Transmit
ACK
N
Y
RI?
SOH?
RI?
Broadcast?
Y
Send
Packet
Transmit
Free Buffer
Enquiry
N
Y
ACK?
Y
N
No Activity
for 41
uS?
Y
Broadcast
Enabled?
Y
N
Set NID=ID
Start Timer:
T=(255-ID)
x 73 us
Activity
On Line?
N
Y
N
No
Activity
for 37.4
us?
N
Y
DID
=0?
N
Y
Was Packet
Broadcast?
N
No
Activity Y
for 37.4
us?
N
N
Y
Y
NAK?
1
Set TA
DID
=ID?
N
Y
Write Buffer
with Packet
Set TA
Pass the
Token
No
Activity
for 37.4
us?
CRC
OK?
Y
LENGTH N
OK?
Y
DID
=0?
N
DID
=ID?
Y
SEND ACK
N
Y
Set RI
N
N
Increment
NID
Set TMA
Y
N
T=0?
Y
ACK?
- 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 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.
* Reconfig timer is programmable via setup2 register bits 1, 0.
Note - All time values are valid for 5 Mbps.
FIGURE 1 - COM20020ID OPERATION
8
ETC [ ETC ]
