TMC2072_07 Datasheet, PDF (25/106 Pages) SMSC Corporation – Peripheral Mode CircLink™ Controller

Peripheral Mode CircLink™ Controller
Datasheet
Chapter 2 Functional Description
2.1
Communication Specification
- Data transfer bit rate
78.125 kbps to 2.5 Mbps (at 20 MHz Xtal), (5 Mbps at 40-MHz Xtal)
- The max. number of nodes
31 (ID = 00 is not available for user)
- Data transfer check
Only the destination node can check data transfer. Other nodes,
however, can receive (monitor) the same data.
- Protocol
Enhanced version of ARCNET (token passing)
- Packet size
256 bytes max. (User area: 253 bytes max.)
2.2
Message Class
The following five classes of messages are identical to those in the ARCNET protocol. Refer to the
ARCNET Controller COM20020 Rev. D Datasheet for more details.
ITT (Token)
ALERT EOT
DID
DID
FBE (Free Buffer Enquiries)
ALERT ENQ
DID
DID
ACK (Acknowledgements)
ALERT ACK
NAK (Negative Acknowledgements)
ALERT NAK
PACKET (Data Packets)
ALERT SOH
SID
DID
DID
CP _{DATA X n} CRC CRC
N : MAX253
(ARCNET Layer)
SMSC TMC2072
Page 25
DATASHEET
Revision 0.1 (06-07-07)