Bad boot and RST pushbutton doesn't work

Started by MarioTest, June 09, 2016, 11:20:42 AM

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We are investigating on some strange SOM behaviour: sometimes after power-on we have no boot and the RST pushbutton has no effect. It is necessary to cycle the power in order to have proper boot.

Why the voltage supervisor U3 - MCP130T-300I/TT has been connected to WARMRSTN and not to PWRONRSTN ?
Actually PWRONRSTN has a simple RC (10k 22uF). Probably a voltage supervisor performs better.

Any hint ?


Make sure that you initialize pin A10 as input, else you would be unable to reset the board via the button. The warm reset signal should be used as an input (as in our case it is connected to a push button) or output (in order to reset connected devices during a POR). It cannot be used for both because of an errata with the clocking of the debounce circuitry.

I tested the reset and it seems to work fine here, so I would also recommend you to test with the official image provided by Olimex.

Best regards,
Technical support and documentation manager at Olimex