COM20020I_0609 Datasheet, PDF (10/69 Pages) SMSC Corporation – 5Mbps ARCNET (ANSI 878.1) Controller with 2K x 8 On-Chip RAM

5Mbps ARCNET (ANSI 878.1) Controller with 2K x 8 On-Chip RAM
Reconfigure
Timer has
Timed Out
Power On
Send
Reconfigure
Burst
Read Node ID
Write ID to
RAM Buffer
1
Set NID=ID
Start
Reconfiguration
Timer (420 mS)*
Y
Invitation
N
to Transmit to
this ID?
N
Y
TA?
Broadcast?
N
Y
Send
Packet
Transmit
NAK
Transmit
ACK
Y
Was Packet
Broadcast?
N
No
Activity
Y
for 37.4
us?
N
Set TA
N
Y
ACK?
Set TMA
Y
Free Buffer
Enquiry to
this ID?
Y
N
RI?
N
Y
N
SOH?
Y
N
RI?
Write SID
to Buffer
Transmit
Free Buffer
Enquiry
No
Activity
Y
DID ^Y
=0?
N for 37.4
Y
N ^us?
N
Broadcast ^N
ACK?
Y
N
NAK?
Set TA
DID
=ID?
YN
Enabled?
Y
1
Write Buffer
with Packet
Pass the
Token
Increment Y
No
Activity
N
NID
for 37.4
us?
CRC ^N
OK?
Y
LENGTH ^N
OK?
Y
- 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.
Y
DID
=0?
N
DID ^N
=ID?
Y
SEND ACK
Set RI
No Activity ^N
for 41
uS?
Y
Set NID=ID
Start Timer:
T=(255-ID)
x 73 us
Activity Y
On Line?
N
N
T=0?
Y
Figure 1 - COM20020I 3V Operation
SMSC COM20020I 3.3V Rev.E
Page 10
DATASHEET
Revision 09-11-06