COM20020I-HD Standard Microsystems (SMSC), COM20020I-HD Datasheet - Page 62

• Manufacturer Part Number: COM20020I-HD
• Manufacturer: Standard Microsystems (SMSC)

Specifications of COM20020I-HD

• Number Of Transceivers: 1
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (typ): 5V
• Operating Supply Voltage (min): 4.5V
• Operating Temperature (max): 85C
• Operating Temperature (min): -40C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Lead Free Status / RoHS Status: Not Compliant

Revision 12-05-06
D0-D7
A0-A2
nCS
nDS
*
***: nCS may become active after control becomes active, but the data setup time will now
Note 1:
**Note 2: Any cycle occurring after a write to the Address Pointer Low Register
DIR
t10
t11
T
T
T
T
t1
t2
t3
t4
t5
t6
t7
t8
t9
ARB
ARB
ARB
opr
Figure 8.10 - Non-Multiplexed Bus, 68XX-Like Control Signals; Write Cycle
be 30 nS measured from the later of nCS falling or Valid Data available.
is the period of operation clock. It depends on CKUP1 and CKUP0 bits
is the Arbitration Clock Period
is identical to T
is twice T
Address Setup to nDS Active
Address Hold from nDS Inactive
nCS Setup to nDS Active
nCS Hold from nDS Inactive
DIR Setup to nDS Active
Cycle Time (nDS
DIR Hold from nDS Inactive
Valid Data Setup to nDS High
Data Hold from nDS High
nDS Low Width
nDS High Width
Write cycle for Address Pointer Low Registers occurring after an access to
Data Register requires a minimum of 5T
the leading edge of the next nDS.
requires a minimum of 4T
The Microcontroller typically accesses the COM20020 on every other cycle.
Therefore, the cycle time specified in the microcontroller's datasheet
of the next nDS.
should be doubled when considering back-to-back COM20020 cycles.
opr
if SLOW ARB = 1
Parameter
opr
t1
if SLOW ARB = 0
to Next Time
t5
t3
DATASHEET
ARB
from the trailing edge of nDS to the leading edge
)**
VALID
Page 62
ARB
t10
from the trailing edge of nDS to
5Mbps ARCNET (ANSI 878.1) Controller with 2K x 8 On-Chip RAM
VALID DATA
4T
30***
t8
min
15
10
10
10
10
20
20
ARB
5
0
*
max
t9
t2
t7
Note 2
t11
t4
t6**
units
nS
nS
nS
nS
nS
nS
nS
nS
nS
nS
nS
t6
SMSC COM20020I Rev D
Datasheet