DNA/DNR-429-512/566 ARINC 429 Layer
Chapter 1
7
Introduction
Tel: 508-921-4600
www.ueidaq.com
Vers:
4.5
Date: December 2013
DNx-429-Chap1x.fm
© Copyright 2013
United Electronic Industries, Inc.
As stated in the ARINC specification, the following detection levels are required
for the three signal states:
State
Differential Voltage
ONE
+6.5 V to +13 V
NULL
+2.5 V to -2.5 V
ZERO
-6.5 V to -13 V
If the received signal for any state is outside the specified range, the chip
rejects the data.
The board can operate at either of two speeds, 100kHz or 12.5kHz, which is
software selectable on a per channel or port pair basis (see page 10). The
transmission medium for an ARINC 429 bus is 78-ohm, twisted, shielded-pair
cable, grounded at both ends and at any break in the cable shield. Each bus
has only one transmitter and up to 20 receivers. Since data transmission is uni-
directional only, transmitters and receivers are on separate ports.
The waveform characteristics must conform to the specifications illustrated in
Figure 1-3
.
C
D
A First half of pulse 5usec ± 5% B/2 ± 5%
B Full pulse cycle 10 usec ±2.5% 1/bit rate ± 5%
C Pulse Rise Time 1.5 ±0.5 usec 10 ± 5 usec
D Pulse Fall Time 1.5 ±0.5 usec 10 ± 5 usec
Received
Voltage
HI 6.5V to 13 V
NULL -2.5V to +2.5V
LOW -6.5V to -13V
Hi Speed Low Speed
HI
NULL
LOW
TRANSMITTED VOL
TAGE
A
B
Figure 1-3. ARINC 429 Waveform Characteristics
