High-Speed CAN Hardware

High-speed CAN interfaces can communicate with devices using

transfer rates up to 1 Mb/s. Typical high-speed devices include antilock

brake systems, engine control modules, and emissions systems.

Low-Speed/Fault-Tolerant CAN Hardware

Low-speed/fault-tolerant CAN interfaces can communicate with

devices up to 125 kb/s and offer transceivers with fault-tolerant

capabilities. Typical low-speed/fault-tolerant devices in an automobile

include comfort devices such as seat and mirror adjusters.

Single-Wire CAN Hardware

Single-wire CAN interfaces can communicate with devices at rates up

to 33.3 kb/s (88.3 kb/s in high-speed mode). Typical single-wire

devices within an automobile include comfort devices such as seat and

mirror adjusters.

Software-Selectable CAN Hardware

You can configure the software-selectable CAN interface for high-speed,

low-speed/fault-tolerant, or single-wire CAN. Multiple-transceiver

hardware offers the perfect solution for applications that require a

combination of communications standards.

NI-CAN Communications Software

National Instruments ships CAN devices with NI-CAN software for

Windows 2000/NT/XP/Me/98. NI-CAN software includes device

drivers that you can use for application development and firmware that

runs on the embedded Intel 80386EX microprocessor. The

NI-CAN device drivers are full 32-bit drivers designed for

Windows 2000/NT/XP/Me/98. These device drivers are compatible

with NI LabVIEW and LabWindows/CVI as well as standard

programming environments such as Microsoft Visual C/C++, Borland

C/C++, and Visual Basic 6. The firmware implements time-critical

features provided by the NI-CAN software. NI-CAN software provides

flexible yet easy-to-use functions for configuration and I/O on CAN.

The Intel 80386EX microprocessor on an NI-CAN interface provides

the operating environment for the CAN protocol communications stack.

CAN specifies timing requirements to ensure reliable, deterministic bus

operation. In a typical system, a National Instruments CAN interface must

provide the necessary system responsiveness. Because the majority of the

CAN protocol executes on the embedded Intel 80386EX microprocessor

on NI CAN interfaces, you can achieve improved response to incoming

messages. Embedded CAN protocol stack execution also results in more

deterministic network performance because the onboard microprocessor

is dedicated to CAN communication activities.

CAN Programming

With NI-CAN software, you can import CAN channel database files

that use the Vector format (.dbc). A CAN frame can contain multiple

values. By importing scaling information from the database files, you

can easily convert these values into channels with engineering units

(such as °C or kPa). You can either import the scaling information

directly into an application or into Measurement & Automation

Explorer (MAX), where you can edit channels. Alternatively, you can

configure channels directly in MAX.

NI-CAN software provides two different application programming

interfaces (APIs) – channel and frame, with which you can develop

applications customized to your test and simulation requirements.

The channel API provides access to the CAN bus in easy-to-use

engineering units, using channels. Therefore, it is recommended for

customers who are new to NI-CAN. The channel API simplifies

multiple device integration and synchronization. With the frame API,

which provides lower-level access to the CAN bus, you can read and

write raw frames on the network. The frame API is recommended for

users that require low-level access to the CAN bus.

Controller Area Network (CAN) Interfaces