COM20020I3V-HT SMSC, COM20020I3V-HT Datasheet - Page 35

• Manufacturer Part Number: COM20020I3V-HT
• Description: Network Controller & Processor ICs ARCNET Contrllr
• Manufacturer: SMSC

Specifications of COM20020I3V-HT

• Product: Controller Area Network (CAN)
• Number Of Transceivers: 1
• Data Rate: 5 Mbps
• Supply Voltage (max): 3.465 V
• Supply Voltage (min): 3.135 V
• Supply Current (max): 35 mA
• 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

6.3
The integration of the 2K x 8 RAM in the COM20020I 3V represents significant real estate savings. The most obvious
benefit is the 48 pin package in which the device is now placed (a direct result of the integration of RAM). In addition, the
PC board is now free of the cumbersome external RAM, external latch, and multiplexed address/data bus and control
functions which were necessary to interface to the RAM. The integration of RAM represents significant cost savings
because it isolates the system designer from the changing costs of external RAM and it minimizes reliability problems,
assembly time and costs, and layout complexity.
SMSC COM20020I 3.3V Rev.E
5Mbps ARCNET (ANSI 878.1) Controller with 2K x 8 On-Chip RAM
BIT
1,0
Internal Ram
Reconfiguration
Timer 1, 0
D0-D7
BIT NAME
I/O Address 02H
High
RCNTM1,0 These bits are used to program the reconfiguration timer as a
Address Pointer Register
Figure 8 – Sequential Access Operation
SYMBOL
I/O Address 04H
11-Bit Counter
Data Register
I/O Address 03H
DATASHEET
function of maximum node count. These bits set the time out
period of the reconfiguration timer as shown below. The time
out periods shown are for 5 Mbps.
Note*: The node ID value 255 must exist in the network for
26.25 mS timeout to be valid.
RCNTM1
Low
0
0
1
1
Page 35
Data Bus
Memory
RCNTM0
Address Bus
Memory
8
0
1
0
1
11
DESCRIPTION
Time Out Period Max Node Count
420 mS
105 mS
52.5 mS
26.25 mS*
INTERNAL
2K x 8
RAM
Up to 255 nodes
Up to 64 nodes
Up to 32 nodes
Up to 16 nodes
Revision 09-11-06