5.0 System Description ....................................................................................................................................................................... 14
Appendix A: NOSYNC and EF Bit Functions ...................................................................................................................................... 56
Appendix B: Interface Circuit Diagram to ISA BUS ............................................................................................................................. 58
Appendix C: Data Sheet Revision History .......................................................................................................................................... 59
2007-2016 Microchip Technology Inc.
DS00002261A-page 3
COM20019I
1.0
1.1
INTRODUCTION
General Description
COM20019I is a member of the family of Embedded ARCNET Controllers from Microchip. The device is a general pur-
pose communications controller for networking microcontrollers and intelligent peripherals in industrial, automotive, and
embedded control environments using an ARCNET protocol engine. The flexible microcontroller and media interfaces,
eight-page message support, and extended temperature range of the COM20019I make it the only true network con-
troller optimized for use in industrial, embedded, and automotive applications. Using an ARCNET protocol engine is the
ideal solution for embedded control applications because it provides a deterministic token-passing protocol, a highly reli-
able and proven networking scheme, and a data rate of up to 312.5 Kbps when using the COM20019I.
A token-passing protocol provides predictable response times because each network event occurs within a predeter-
mined time interval, based upon the number of nodes on the network. The deterministic nature of ARCNET is essential
in real time applications. The integration of the 2Kx8 RAM buffer on-chip, the Command Chaining feature, the maximum
data rate, and the internal diagnostics make the COM20019I the highest performance embedded communications
device available. With only one COM20019I and one microcontroller, a complete communications node may be imple-
mented.
For more details on the ARCNET protocol engine and traditional dipulse signaling schemes, refer to the ARCNET Local
Area Network Standard, available from Standard Microsystems Corporation or the ARCNET Designer's Handbook,
available from Datapoint Corporation.
For more detailed information on cabling options including RS485, transformer-coupled RS-485 and Fiber Optic inter-
faces, refer to the following technical note which is available from Standard Microsystems Corporation: Technical Note
7-5 - Cabling Guidelines for the COM20020 ULANC.
DS00002261A-page 4
2007-2016 Microchip Technology Inc.
COM20019I
2.0
PIN CONFIGURATION
FIGURE 2-1:
28-PIN PLCC PIN ASSIGNMENTS (TOP VIEW) AND ORDERING INFORMATION
nM U X
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
VDD
nC S
nIN TR
n R E S E T IN
nPULSE2
R X IN
nT X E N
VSS
A1
/A L E
AD0
AD1
AD2
D3
D4
D5
D6
D7
VSS
n R D /n D S
n W R /D IR
25
nW R /D IR
26
27
28
1
2
3
4
24
23
22
21
20
19
18
17
16
15
14
13
12
nP U LS E 1
X TA L 2
X TA L 1
VDD
VSS
N /C
D7
nCS
n IN TR
n R E S E T IN
n TX E N
R X IN
n P U LS E 2
nR D /nD S
VDD
A 0/nM U X
A1
A 2/A L E
n P U LS E 1
X TA L 2
X TA L 1
AD0
5
6
7
8
9
10
11
D3
D5
D6
D4
AD1
AD2
VSS
Pa cka g e s: 24 -P
PLCC
o r 2 8 -P in P L C C
Package: 28-Pin
in D IP
O rd e rin g
Information:
:
Ordering
In fo rm a tio n
C O M 20019
I
P
PA C K A G E T Y P E : P = P la stic, L JP = P L C C
TEMP RANGE:
(B la n k) = C o m m e rc ia l: 0 °C to + 7 0°C
I = In du stria l: -4 0 °C to + 8 5°C
2 00 1 9 = U n ive rsa l L oc a l A re a N e tw o rk C o n trolle r
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
