com90c66 Standard Microsystems Corp., com90c66 Datasheet - Page 3

• Manufacturer Part Number: com90c66
• Description: Arcnet Controller/transceiver With At Interface And On-chip Ram Corporation
• Manufacturer: Standard Microsystems Corp.

For other machines, the IOCHRDY signal may
be briefly negated to give the device the extra
time necessary to support the faster machines.
Aside from the implementation of a 16-bit data
bus interface, the remaining bus interface logic
is identical to that found in the SMSC
COM90C65, which contains all the support logic
circuitry.
The ARCNET Local Area Network is a token
passing network which operates at a 2.5 Mbps
data rate.
predictable
network event occurs within a known time
interval.
Throughput can be reliably predeter-
A token passing protocol provides
response
nBSLED
nTXLED
INTR
GND
AEN
D10
D11
D12
D13
D14
D15
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
times
11 10
33 34 35 36 37 38
PACKAGE: 84-Pin PLCC
Ordering Information: COM90C66 LJP
9 8 7 6 5 4 3 2 1 84 83 82 81 80 79 78 77 76 75
because
COM90C66
PIN CONFIGURATION
39
40 41 42 43 44 45 46 47 48 49 50 51 52 53
each
3
mined based upon the number of nodes and
their expected traffic.
The
configuration and automatically reconfigures the
token passing order as new nodes are added or
deleted from the network.
The COM90C66 performs address recognition,
CRC
acknowledgement,
management
interfaces directly to the IBM PC/AT or
compatibles. The internal 2K x 8 RAM buffer is
used to hold up to four data packets with a
maximum length of 508 bytes each.
COM90C66
checking
functions.
74
73
72
71
70
69
68
67
66
65
64
63
62
61
60
59
58
57
56
55
54
and
establishes
BALE
nSBHE
nOWS
IOCHRDY
nMEMCS16
nIOCS16
GND
nMEMW
nMEMR
nIOW
nIOR
nTOPL
nTOPH
NC
NC
CACLK
CLK
RXIN
nPULSE2
nPULSE1
nPROM
and
generation,
The
other
the
C0M90C66
network
network
packet