NMEA 2000

NMEA Docs They’re generally paid, however the following is available online: National-marine-electronics-association-nmea-2000-standard-for-serial-data-networking-of-marine-electronic-devices-main-document NMEA 2000 Basics 250kbps CAN Bus 29bit identifier (ISO11783 standard) 8 byte data field Open Source Libraries The NMEA2000 library by Timo Lappalainen basically makes NMEA2000 possible for the masses (it’s a big and complex standard!): https://github.com/ttlappalainen/NMEA2000

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Troubleshooting CAN Bus

A few tips on trying to get a CAN bus to work… Baud Rate Check the baud rate is good using an oscilloscope.  If the baud is 250k for instance, that's 1 second / 250000 = 4uS per bit. You should be able to see 4uS individual bits being sent (the SOF at the start of a […]

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Implementing CAN Bus In Software

Some notes about the bus signals CAN bus needs the terminators fitted to the cabling.  If not the signals you see with a scope on the RX side of the transceiver will be wrong! The CAN bus TX line (pre transceiver) idles high.   The CAN bus RX line (pre transceiver) see's everything you TX too (it needs […]

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CAN Transceivers

3.3V CAN transceivers 3.3V and 5V CAN transceivers are interoperable because High Speed CAN physical layer uses differential signaling that is the same for a 3.3V and 5V CAN transceiver. In addition both the 3.3V and 5V CAN transceivers have the same wide common mode range accommodating not only the typical signaling but also providing wide margin for ground […]

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CAN vs RS485

CAN (Controller Area Network) and RS485 are both popular standards in fieldbus systems. RS485 only addresses layer 1 (the physical layer) CAN also adds layer 2 (the data link layer) in the OSI model. Both are based on multiple nodes connected to a shared serial bus with one or more acting as a master being possible. […]

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.CAN Bus General

CAN bus ("Controller Area Network") is widely used in the automotive, aerospace, maritime, industrial and medical industries. ​Bus General Microcontroller CAN Bus Pins (Pre CAN Transceiver) High = recessive bus state (bus not driven), Low = dominant bus state (bus is driven by transceiver) Multi Master serial bus. TX and RX pins from the bus transceiver: The CAN bus TX line (pre transceiver) […]

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