# Enable GPIO Interrupt for host firmware update

**URL:** <https://discuss.blues.com/t/enable-gpio-interrupt-for-host-firmware-update/2461>\
**Category:** Firmware\
**Created:** [November 25, 2024, 2:51pm UTC](https://discuss.blues.com/t/enable-gpio-interrupt-for-host-firmware-update/2461 "2024-11-25T14:51:18Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![Thareeq](https://avatars.discourse-cdn.com/v4/letter/t/f19dbf/32.png) [@Thareeq](https://discuss.blues.com/u/Thareeq)\
**Post date:** [November 25, 2024, 2:51pm UTC](https://discuss.blues.com/t/enable-gpio-interrupt-for-host-firmware-update/2461/1 "2024-11-25T14:51:18Z")

</div>

Hi, I am trying to get an GPIO interrupt on my host device when a new host firmware is updated in the notehub. I cannot find such a configuration neither in ATTN pins nor in AUX pins. I found something similar for outboard firmware update but not something I needed. Is there any options to receive a gpio interrupt when updating the host firmware in notehub?

---

<div class="post-metadata">

**Author:** ![abucknall](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.blues.com/abucknall/32/1335_2.png) [@abucknall](https://discuss.blues.com/u/abucknall)\
**Post date:** [November 25, 2024, 6:31pm UTC](https://discuss.blues.com/t/enable-gpio-interrupt-for-host-firmware-update/2461/2 "2024-11-25T18:31:26Z")

</div>

Hi @Thareeq, welcome!

If I’m understanding your question correctly, while there’s no direct command to set the `ATTN` pins to monitor for a host DFU change, you could try monitoring for an environment variable change. When you upload a new host firmware in Notehub, the envar `_fw` will update to the “Name of a host firmware binary”.

You could try something like:

```auto
{
  "req": "card.attn",
  "mode": "arm,env"
}

```

Where the ATTN pin is connected to an interrupt on your host MCU.

You can read more about the reserved environment variables [here](https://dev.blues.io/guides-and-tutorials/notecard-guides/understanding-environment-variables/#reserved-environment-variables).

Thanks,  
Alex