10 Mbps ARCNET (ANSI 878.1) Controller with 2Kx8 On-Board RAM
Datasheet
BIT
BIT NAME
SYMBOL
DESCRIPTION
4,3 Extended
Timeout 1,2
ET1, ET2
These bits allow the network to operate over longer
distances than the default maximum 1 mile by controlling
the Response, Idle, and Reconfiguration Times. All nodes
should be configured with the same timeout values for
proper network operation. For the COM20022I 3V with a
20 MHz crystal oscillator, the bit combinations follow:
Reconfig
Response Idle Time
Time
(mS)
420
420
420
210
ET2
0
ET1
0
Time (μS)
298.4
149.2
74.7
(μS)
328
164
82
0
1
1
0
1
1
18.7
20.5
Note: These values are for
10Mbps and RCNTMR[1,0]=00.
Reconfiguration time is changed by the RCNTMR1
and RCNTMR0 bits.
2
Backplane
BACK-
PLANE
A logic "1" on this bit puts the device into Backplane Mode
signaling which is used for Open Drain and Differential
Driver interfaces.
1,0 Sub Address 1,0
SUBAD 1,0 These bits determine which register at address 07 may be
accessed. The combinations are as follows:
SUBAD1
SUBAD0
Register
Tentative ID
Node ID
Setup 1
0
0
1
1
0
1
0
1
Next ID
See also the Sub Address Register.
SMSC COM20022I 3V
Page 41
Revision 02-27-06
DATASHEET
SMSC [ SMSC CORPORATION ]
