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I'm trying to use wake-from-halt on my Raspberry Pi A+, but it does not work. According to elinux.org/RPI_safe_mode#cite_note-1 When using bootcode.bin dated 12/04/2012 or later, the same two pins (5 & 6) can be momentarily shorted to wake the Raspberry Pi from the halted state. But this does not work :(

I also tried updating the bootloader. Is this feature implemented for the A+?

uname -a: Linux raspberrypi 4.14.34+ #1110 Mon Apr 16 14:51:42 BST 2018 armv6l GNU/Linux

The script to halt the raspberry pi is working without any problems

Ingo
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TOAOGG
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  • Wake from halt? You mean booting from Etherrnet? – not2qubit May 09 '18 at 20:14
  • According to https://elinux.org/RPI_safe_mode#cite_note-1

    When using bootcode.bin dated 12/04/2012 or later, the same two pins (5 & 6) can be momentarily shorted to wake the Raspberry Pi from the halted state.

    But this does not work :(

     – TOAOGG May 09 '18 at 20:22
  • Maybe the A+ has RUN pins (or holes...) marked on the board you could use instead? Those should not require any firmware revision. – goldilocks May 09 '18 at 20:38
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    Aha, did you try this? – not2qubit May 09 '18 at 20:41
  • The p6 works and will be my backup solution, as it only resets the board. With the wake-from-halt I could halt the board and later start it to safe power. I will probably end up with a timer in my application that brings the pi into halt after some time, which lets me use p6 to wake it again – TOAOGG May 09 '18 at 20:44
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    P6 -> that's what I was thinking about with the "RUN pins". – goldilocks May 09 '18 at 21:02

1 Answers1

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I an not sure you can actually "halt" the Pi with current Raspbian (although you may be able to write assembler to do so); all the normal shutdown commands run the same code.

The pin 5/6 does work (subject to a few caveats) - although I haven't tried on an A+ it works on all the B models.

If you want safe shutdown, Raspbian now includes code to do this dtoverlay=gpio-shutdown you don't need ANY code. See Raspberry Pi 3 model B "dtoverlay=gpio-shutdown"

Milliways
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  • I explore the halt vs power off call stack through the kernel in an answer of mine. It appears a shutdown through the reboot syscall with LINUX_REBOOT_CMD_POWER_OFF or LINUX_REBOOT_CMD_HALT , which is the case for shutdown -h triggers the system to prime for reset, this is the intended use case of the run pin IIRC – crasic Mar 04 '19 at 07:32