DNA/DNR-429-512/566 ARINC 429 Layer
Chapter 1
8
Introduction
Tel: 508-921-4600
www.ueidaq.com
Vers:
4.5
Date: December 2013
DNx-429-Chap1x.fm
© Copyright 2013
United Electronic Industries, Inc.
1.6.1
Word Format
Each ARINC-429 BNR word is a 32-bit value containing 5 fields, as shown in
Figure 1-4
.
Figure 1-4. General ARINC Word Format
The bits have the following meanings:
•
Bit 32 — parity bit, used to determine validity of word
•
Bits 31, 30 — Sign/Status Matrix (SSM), indicates status of data
OP
[1 1] indicates data is normal
TEST
[1 0] indicates data comes from a test source
FAIL
[0 0] indicates a hardware failure causing data to be missing
NCD
[0 1] indicates data missing because of non-hardware reason
•
Bits 11 to 29 — contain the data (bit-field, BCD, BNR, or mixed)
•
Bits 9 and 10 — Source/Destination Identifiers (SDI) indicate the
intended receiver or the transmitter sending the data
•
Bits 1 to 8 — a label, in octal, identifying the data type
NOTE:
Use of SDI and SSM is not mandatory.
Although the order in which bits are transmitted/received is somewhat complex,
the HI-3282 chips handle the decoding automatically. The bits are transmitted on
the ARINC bus in the following order.
8,7,6,5,4,3,2,1, 9,10,11,12, . . . 32
The Label (first 8 bits) is transmitted before the data (MSB first). After the label
is sent, the LSB of each byte is transmitted first.
1.6.1.1
Scheduler
ARINC Data
Format
The Scheduler ARINC Data Format is as shown in the table below.
ARINC data is transferred via the ARINC-429 bus whenever a corresponding
scheduler command entry is set for execution.
ARINC data should be preformatted in a form that is common for industry
protocol controllers such as the Holt HI-3282.
Note that the ARINC serial communication standard numbers bits from 32
(MSB) to 1 (LSB). The UEI DNx-429-566/512 numbers them from 31 to 0, and
the Holt controllers use two 16-bit words with bits numbered from 15 to 0. Also
note that only LABEL, PARITY, SSM, and SDI bits are strictly defined by the
ARINC-429 standard. The rest of the bits may be used as a payload by various
sub-protocols.
SDI
DISCRETES
PAD
DATA
SSM
P
LSB
MSB
LABEL
1
32 31 30 29
11 10 9 8
Bit
Name
Description
Reset State
31-0
ADATA
ARINC data
0
