COM20022I3V-HD SMSC, COM20022I3V-HD Datasheet - Page 14

• Manufacturer Part Number: COM20022I3V-HD
• Description: Network Controller & Processor ICs ARCNET Contrllr
• Manufacturer: SMSC

Specifications of COM20022I3V-HD

• Data Rate: 10 Mbps
• Supply Voltage (max): 3.465 V
• Supply Voltage (min): 3.135 V
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Package / Case: TQFP-48
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

4.6.1
4.6.2
4.6.3
Revision 02-27-06
precisely determined. The line idles in a spacing (logic "0") condition. A logic "0" is defined as no line
activity and a logic "1" is defined as a negative pulse of 50nS duration. A transmission starts with an
ALERT BURST consisting of 6 unit intervals of mark (logic "1"). Eight bit data characters are then sent,
with each character preceded by 2 unit intervals of mark and one unit interval of space. Five types of
transmission can be performed as described below:
Invitations To Transmit
An Invitation To Transmit is used to pass the token from one node to another and is sent by the following
sequence:
Free Buffer Enquiries
A Free Buffer Enquiry is used to ask another node if it is able to accept a packet of data. It is sent by the
following sequence:
Data Packets
A Data Packet consists of the actual data being sent to another node. It is sent by the following sequence:
An ALERT BURST
An EOT (End Of Transmission: ASCII code 04H)
Two (repeated) DID (Destination ID) characters
An ALERT BURST
An ENQ (ENQuiry: ASCII code 85H)
Two (repeated) DID (Destination ID) characters
An ALERT BURST
An SOH (Start Of Header--ASCII code 01H)
An SID (Source ID) character
Two (repeated) DID (Destination ID) characters
A single COUNT character which is the 2's complement of the number of data bytes to follow if a short
packet is sent, or 00H followed by a COUNT character if a long packet is sent.
N data bytes where COUNT = 256-N (or 512-N for a long packet)
Two CRC (Cyclic Redundancy Check) characters. The CRC polynomial used is: X
ALERT BURST
BURST
ALERT
ALERT BURST
SOH
SID
DID
DATASHEET
ENQ
EOT
DID
Page 14
COUNT
10 Mbps ARCNET (ANSI 878.1) Controller with 2Kx8 On-Board RAM
DID
data
DID
data
CRC
DID
DID
CRC
16
SMSC COM20022I 3V
+ X
15
+ X
Datasheet
2
+ 1.