ISO1050: Chip selection consult

Part Number: ISO1050
Other Parts Discussed in Thread: ISO1044

Hi Team,

Is that possible for CAN device to achieve chip selection function like SPI communication way? By enable/disable power supply or others way? Thanks.



  • Hi Stanley,

    Thank you for reaching out to us!

    ISO1050 complies with the ISO11898-2 physical layer. Many high-level industrial protocols embrace ISO-11898-2 as their physical layer. Commonly, CAN devices are used in multi-master communication systems, and the CAN nodes are identified by the 11-bit identifier. This application report provides an introduction to the CAN and its protocol.

    Having that said, one can always design a new high-level protocol that works with the ISO11898-2 physical layer. If you choose to select CAN nodes by enabling or disabling their power supplies, you are most likely not using the standard high-level CAN protocol. Therefore, you must consider/design a custom protocol for your system that works well with the ISO11898-2 physical layer.

    Below are the characteristics of ISO1050 when it is powering down.
    1) The output RXD is in high-impedance when Vcc1 is powered down. You may need to add pull-up or pull-down to meet your system.
    2) It takes 300 microseconds to resume regular activity after supplies have returned to valid levels.
    3) It is also essential to ensure the TXD voltage does not exceed 0.5V of Vcc1. Hence, it is recommended to drive the TXD to ground before powering down Vcc1.

    FYI, ISO1044 is the newest isolated CAN device that has better performance than ISO1050.