Tag: geekstuff

STM32 Nucleo boards and blackmagic probe.

I recently purchased a STM32F7 Nucleo boards to play around with Chibios.  These boards feature a integrated STlink debugger, I however do most of my development using a custom built debugger based on the blackmagic probe.  This has the advantage of being easily connectable to GDB via emulating gdbserver on it’s virtual serial port.

Unfortunately there doesn’t look like there is a documented way of connecting a 3rd party debugger to the Nucleo board but reading the schematics showed an answer in the form of the CN4 jumper block.

In order to connect a the black magic probe to the Nucleo board simply remove the jumpers from CN4 on the ST-Link .  You can then access the SWDIO pins on the main MCU as shown in the list below.

  1. SWCLK/TCK
  2. NO-CONNECT
  3. SWDO/TMS
  4. NO-CONNECT

You will also need to connect the ground pin of the blackmagic probe to a ground pin on the Nucleo board (I used one of the ground pins which have jumpers on them which are used for feet on the board.

And here is a picture of the board.

Anatomy of a bicycle chain

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I changed the chain on my bicycle awhile ago and decided to keep the old one and recycle it.  I haven’t decided what or if I’m going to us it for yet but was curious about the wear on its components.  So I used a chain too to remove 3 of the links so I could completely disassemble one of the links.
Once I disassembled it I could see that the main component that show wear is the connecting pins.  They have quit obvious grooves which is probably the main thing the cause train stretch.  Surprisingly I couldn’t see any obvious wear on the two bearings.  I also saw some wear on the silver coloured connecting links.
It was also quite interesting how the rear sprocket had worn.  It looks like some of the teeth have actually bent out of shape.

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