2
\$\begingroup\$

I have to provide an update mechanism to a product. Currently, I implemented a bluetooth upgrade mechanism, updated pushed via Bluetooth. In case something goes very wrong, marketing asking for a recovery method, which is reasonable.

The uP I use has an embedded bootloader (ROM). I can use this as the bullet proof method. This one requires some pin to be pulled high, original design we didn't expose this, it was a pad on the board. Now, I need some way to expose and give user a way to make this work. The thinking is to use a special power on/off button. Currently, we use a mechanical button, when off, no power to system including CPU. The idea is to find a button, if you keep pressed at the bottom, this pin is pulled high and if you have the right software on PC, things will start to move.

What do you think about this approach? (I am worried about hackers) and where can I find such a switch?

\$\endgroup\$
2
  • \$\begingroup\$ What do you mean "such a switch" ? Sounds like a standard pushbutton will do just fine. You just want to implement functionality where you trigger an action if the pushbutton is held for a while (as opposed to just a press). So, you either need the analog circuitry to implement the pin High only upon X hold period, or you can do this in the code with an interrupt and timer. \$\endgroup\$ – boardbite Sep 11 '12 at 5:40
  • \$\begingroup\$ @boardbite Not really. I need this pin to be pulled high only when the button is at the dip, but not when it is on. I will put a diagram. \$\endgroup\$ – Ktc Sep 11 '12 at 5:42
2
\$\begingroup\$

Hackers? Once something is out of your physical control you can't stop hackers. Period.

That being said, why not a three position switch where one of the positions is momentary? Here is an example - search on Digikey for switch with the 'Switch Function' set to 'On-Off-Mom'

\$\endgroup\$
1
  • \$\begingroup\$ on-off-mon was what I was looking for.. \$\endgroup\$ – Ktc Sep 12 '12 at 3:28

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.