# CAN termination resistor

**URL:** <https://forum.opencyphal.org/t/can-termination-resistor/289>\
**Category:** Libcanard\
**Created:** [December 13, 2018, 8:50am UTC](https://forum.opencyphal.org/t/can-termination-resistor/289 "2018-12-13T08:50:25Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![Giorgio\_73](https://forum.opencyphal.org/letter_avatar_proxy/v4/letter/g/7ab992/32.png) [@Giorgio\_73](https://forum.opencyphal.org/u/Giorgio_73)\
**Post date:** [December 13, 2018, 8:50am UTC](https://forum.opencyphal.org/t/can-termination-resistor/289/1 "2018-12-13T08:50:25Z")

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How to enable or disable CAN termination resistor in Libcanard project?

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**Author:** ![pavel.kirienko](https://forum.opencyphal.org/user_avatar/forum.opencyphal.org/pavel.kirienko/32/9_2.png) [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\
**Post date:** [December 13, 2018, 9:59am UTC](https://forum.opencyphal.org/t/can-termination-resistor/289/2 "2018-12-13T09:59:32Z")

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Libcanard (or any other implementation known to man) does not concern itself with the physical layer, so you can’t do that.

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**Author:** ![Giorgio\_73](https://forum.opencyphal.org/letter_avatar_proxy/v4/letter/g/7ab992/32.png) [@Giorgio\_73](https://forum.opencyphal.org/u/Giorgio_73)\
**Post date:** [December 19, 2018, 4:05pm UTC](https://forum.opencyphal.org/t/can-termination-resistor/289/3 "2018-12-19T16:05:35Z")

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In Zubax Babel Datasheet (pag 5) it is written:  
“The device has an embedded 120 ohm CAN termination resistor that can be enable and disabled by setting the configuration can.termiantor\_on”  
I thought the same functionality was also implemented in the Libcanard library because it uses the same hardware. It’s incorrect?

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**Author:** ![pavel.kirienko](https://forum.opencyphal.org/user_avatar/forum.opencyphal.org/pavel.kirienko/32/9_2.png) [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\
**Post date:** [December 19, 2018, 4:29pm UTC](https://forum.opencyphal.org/t/can-termination-resistor/289/4 "2018-12-19T16:29:40Z")

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Libcanard is hardware-agnostic, so saying that it uses any particular hardware is incorrect. The hardware abstraction interface does not support CAN termination resistor configuration.

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<div class="post-metadata">

**Author:** ![Giorgio\_73](https://forum.opencyphal.org/letter_avatar_proxy/v4/letter/g/7ab992/32.png) [@Giorgio\_73](https://forum.opencyphal.org/u/Giorgio_73)\
**Post date:** [December 19, 2018, 4:45pm UTC](https://forum.opencyphal.org/t/can-termination-resistor/289/5 "2018-12-19T16:45:27Z")

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Can you tell which PIN the uC on Zubax is connected to CAN termination resistor configuration?

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<div class="post-metadata">

**Author:** ![pavel.kirienko](https://forum.opencyphal.org/user_avatar/forum.opencyphal.org/pavel.kirienko/32/9_2.png) [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\
**Post date:** [December 19, 2018, 5:00pm UTC](https://forum.opencyphal.org/t/can-termination-resistor/289/6 "2018-12-19T17:00:27Z")

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If you’re referring to Zubax Babel, the pin is number 20, Port B, bit 2.