ARINC 429 Bus Interface

v5.0

3

•

Sign/Status Matrix

•Data

•

Source/Destination Identifiers

•Label

The parity bit is bit 32 (the MSB). SSM is the Sign/Status

Matrix and is included as bits 30 and 31. Bits 11 to 29

contain the data. Binary Coded Decimal (BCD) and binary

encoding (BNR) are common ARINC data formats. Data

formats can also be mixed. Bits 9 and 10 are Source/

Destination Identifiers (SDI) and indicate for which

receiver the data is intended. Bits 1 to 8 contain a label

(label words) identifying the data type.

Label words are quite specific in ARINC 429. Each aircraft

may be equipped with different electronic equipment

and systems needing interconnection. A large amount of

equipment may be involved, depending on the aircraft.

The ARINC specification identifies the equipment ID, a

series of digital identification numbers. Examples of

equipment are Flight Management Computers, Inertial

Reference Systems, Fuel Tanks, Tire Pressure Monitoring

Systems, and GPS Sensors.

Transmission Order

The least significant bit of each byte, except the label, is transmitted first, and the label is transmitted ahead of the

data in each case. The order of the bits transmitted on the ARINC bus is as follows:

8, 7, 6, 5, 4, 3, 2, 1, 9, 10, 11, 12, 13 … 32.

Core429 Device Requirements

Core429 can be implemented in several Actel FPGA devices. Table 1 through Table 5 on page 4 provide typical

utilization figures using standard synthesis tools for different Core429 configurations. Table 1 assumes that the label

size is set to 64 and FIFO depth is set to 64.

Figure 3 •

ARINC Data Bit Positions

32

31

11

10

9

LABEL

30

29

1

8

LSB

DATA

PAD

DISCRETES

SDI

P

SSM

MSB

Table 1 •

Device Utilization for One Tx Module

Cells or Tiles

Family

Combinatorial

Sequential

Total

Memory Blocks

Device

Utilization

Fusion

363

147

510

1

AFS600

4%

ProASIC3/E

363

147

510

1

A3PE600

4%

441

146

587

1

APA075

19%

Axcelerator

212

145

357

1

AX125

18%

RTAX-S

258

171

429

1

RTAX250S

10%

Table 2 •

Device Utilization for One Rx Module

Cells or Tiles

Family

Combinatorial

Sequential

Total

Memory Blocks

Devices

Utilization

Fusion

431

233

664

2

AFS600

5%

ProASIC3/E

431

233

664

2

A3PE600

5%

588

236

824

2

APA075

27%

Axcelerator

307

234

541

2

AX125

27%

RTAX-S

350

259

609

2

RTAX250S

14%