LeafLabs Garden

A place to share, learn, and grow...

1. 

   stephanschulz
   Member

   is it possible to get the maple mini to reset itself in case the supply voltage drops too much.
   i am reading that brown out is the keyword.

   thanks for any advice.
   stephan

   Posted 2 years ago #
2. 

   ala42
   Member

   From the data sheet
   

   2.3.10 Power supply supervisor
   The device has an integrated power-on reset (POR)/power-down reset (PDR) circuitry. It is
   always active, and ensures proper operation starting from/down to 2 V. The device remains
   in reset mode when VDD is below a specified threshold, VPOR/PDR, without the need for an
   external reset circuit.
   The device features an embedded programmable voltage detector (PVD) that monitors the
   VDD/VDDA power supply and compares it to the VPVD threshold. An interrupt can be
   generated when VDD/VDDA drops below the VPVD threshold and/or when VDD/VDDA is higher
   than the VPVD threshold. The interrupt service routine can then generate a warning
   message and/or put the MCU into a safe state. The PVD is enabled by software.
   Refer to Table 11: Embedded reset and power control block characteristics for the values of
   VPOR/PDR and VPVD.

   Posted 2 years ago #
3. 

   stephanschulz
   Member

   thanks for the reply.

   i found the section you are quoting here:
   http://www.st.com/web/en/resource/technical/document/reference_manual/CD00171190.pdf

   unfortunately my knowledge does not go deep enough to be able to covert this in to the right lines of code.
   it seems one could set a low and high threshold value and force a reset if the power goes past those thresholds.

   in my case i am controlling a bunch of relays and at some point the maple mini enters a strange state where the on board led quickly fades in and out.
   obviously i have to re-design my circuit about being able to set the brown out would be great too.

   thx

   Posted 2 years ago #
4. 

   ala42
   Member

   The data sheet clearly states that the CPU gets a reset when the volatage is ~2V. You can not change this reset voltage level. You can set up the CPU to cause an interrupt when a specific level is reached.
   The fading LED sounds like the __error() function in util.c. Use a debugger or connect USART1 to find out what causes the problem.
   You could also disconnect the relays to check if they cause the problem.

   Posted 2 years ago #

RSS feed for this topic

Reply

You must log in to post.