How to request a graceful shutdown of your microcontroller project without using an LTC2954.
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More information (including all links, sketches & PDFs in my GitHub):
https://github.com/RalphBacon/172-LTC2954-On-Off-Emulator

The Linear Technology **LTC2954** device allows a single push button on *and* off of your microcontroller (via a P-channel MOSFET). Additionally it can request an emergency shutdown via a user-configurable delay by pressing and holding the aforementioned button for several seconds.

Here's how to emulate the first two features using our previously used (video #123) Auto Shutoff dual MOSFET circuitry with just a couple of extra components.

Compare the two circuits in my GitHub; the one of the left is the original circuit; the other is the modified circuit to allow a graceful shutdown request to be be sent to the µController.

The two additional diodes are just IN4148 small signal diodes. Nothing special!

The shutdown request is serviced by the microcontroller on an interrupt pin. Full details in the video.

More information (including all links, sketches & PDFs in my GitHub):
https://github.com/RalphBacon/172-LTC2954-On-Off-Emulator

### LINKS

Linear Technologies **LTC2954** from RS Components UK Warehouse, about £3 / $4:
https://uk.rs-online.com/web/c/semiconductors/power-management-ics/voltage-supervisors/?searchTerm=LTC2954

**LTC2954** From AliExpress, $10 for 5 pieces free shipping:
http://s.click.aliexpress.com/e/nLNYrk4s

DUAL MOSFET CJMCU-4599 Si4599 N and P Channel MOSFET Expansion Board $1.89 each or $4.08 for 3 pieces:
**Single:** https://www.banggood.com/CJMCU-4599-Si4599-N-and-P-Channel-40V-D-S-MOSFET-Expansion-Board-Module-p-1350610.html?p=FQ040729393382015118&utm_campaign=25129675&utm_content=3897
**3 Pieces:** https://www.banggood.com/3pcs-CJMCU-4599-Si4599-N-and-P-Channel-40V-D-S-MOSFET-Expansion-Board-Module-p-1363266.html?p=FQ040729393382015118&utm_campaign=25129675&utm_content=3897

**Datasheet for LTC2954**:
https://www.analog.com/media/en/technical-documentation/data-sheets/2954fb.pdf

**Datasheet for Si4599** dual MOSFET:
https://www.vishay.com/docs/68971/si4599dy.pdf

Interactive **cheat sheet** for calculating potential (resistor) divider values:
http://www.ohmslawcalculator.com/voltage-divider-calculator

### List of all my videos
(Special thanks to Michael Kurt Vogel for compiling this)
http://bit.ly/YouTubeVideoList-RalphBacon

### My blog article on what happened to my eye (again):
https://ralphbacon.blog/?p=340

More information (including all links, sketches & PDFs in my GitHub):
https://github.com/RalphBacon/172-LTC2954-On-Off-Emulator

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My channel, GitHub and blog are here:
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