Push & Hold (Delay) to Hardware Reset an AVR - How To?

Other Hardware General Electronics
1

I'm looking for a good hardware solution to implement a push-and-hold user reset for an AVR project. I have a button that's essentially a power button tied to an interrupt on the mcu that puts it to sleep and wakes it up. I would like to be able to allow the user to push and hold this same power button (10 seconds, for example) to do a hardware reset in case of firmware problems. I've been told I might be able to find a supervisor IC with a programmable delay that would fit the purpose (and have very low power consumption) but my searching has only returned supervisor ICs with programmable delays in the realm of milliseconds designed to monitor battery voltage.

I'm not sure if I'm on the right path. Can anyone give me any better terms to search for, examples, etc to accomplish this?

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Check out the STM6600:

http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00226957.pdf

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The Ruggeduino: compatible with Arduino UNO, 24V operation, all I/O's fused and protected

3

RuggedCircuits:
Check out the STM6600

I'm looking over the datasheet right now and it looks perfect so far. It's even seems priced well at $1.15 @ 1k compared to some of the other pieces I've found that do far less at the same price. Thanks for the recommendation.

4

555 timer can probably do that,
or a simple rc circuit to the switch, probbly a little less reliable but simple

5

It's even seems priced well at $1.15 @ 1k

It seems like a job for a microcontroller to me. How about an ATtiny4 that's under $0.50 in q100 ? (PIC 10F and Freescale RS08 are also available in that price range.)

Note that avr-gcc does not support tiny4, and it's a bit "odd." Not having to write and maintain firmware might be worth double the price!

Edit: note that the ADK2012 schematics that was published recently (and is supposedly the first detailed glimpse of the Arduino Due) has a PIC10F "Secret Knock" device on it! (connected to the ARM "Erase" pin.)

6

westfw:
It seems like a job for a microcontroller to me. How about an ATtiny4 that's under $0.50 in q100 ? (PIC 10F and Freescale RS08 are also available in that price range.)

An ATtiny4 would certainly work, although you are exactly right that avoiding writing/testing/maintaining firmware is exactly what I'm after here... especially since it's primary purpose is to bail me out in case of firmware problems. That could be a really excellent project to start in the community though replicating this functionality on an ATtiny4. I have a feeling it would get used a lot for a lot of battery powered Arduino projects. I'd use it in a heartbeat and contribute if it were already built and tested! :slight_smile: