LedBorg resets Raspberry Pi

Submitted by sccb1g10 on Tue, 08/20/2013 - 11:12

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LedBorg

Hi,

I am trying to use the LedBorg with a Raspberry Pi version 2, running Raspbian, Kernel 3.6.11+. The problem is that once I atttach the LedBorg onto the Raspberry Pi, the Pi resets and the LedBorg`s LED clips with different light colours. After the Raspberry Pi boots again, the LedBorg seems to be ok, the colour picker and the demos all seem to be working fine.
But it would still be frustrating to have to restart the Pi everytime I attach the LedBorg onto it.

Anyone has any ideas why it`s doing this? I thought it might be something with the GPIOs on the Pi not being properly set but I cannot see where the problem might be.

Thank you,
Silviu

piborg

Tue, 08/20/2013 - 12:14

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Capacitor

Hi Silviu,

The reason the Raspberry Pi is reset when attaching an LedBorg is that a decoupling capacitor is fitted between the 5v and ground (0v), as shown in the LedBorg schematic.

The reason it causes a reset is when first attached the capacitor charges itself from the 5v line, causing the 5v line to drop a small amount briefly, but enough to upset the Raspberry Pi.
The reason for having the capacitor is to stop the logic chip switching on / off from putting noise on the 5v line which would potentially cause the same issue.

There is an image below with the capacitor (labelled C1 on the board) circled in magenta.
If you really wish to prevent the Raspberry Pi resetting when attaching the LedBorg you could carefully remove this capacitor with a soldering iron, however we do not recommend doing this since it may cause problems with the Raspberry Pi and we would not be responsible if it harmed the Raspberry Pi irreparably.

On a side note we do not really recommend attaching devices to the Raspberry Pi whilst it is running, it is an ESD sensitive device and may be damaged depending on what is attached.

Kind regards,
PiBorg.

Images: