Month: August 2017

Adding a custom USB socket to the STM32 NUCLEO-F746

I’m currently building a design on the STM32F7 which I want to later port to a F4-NUCLEO board and eventually my own design so I want to test the USB host without the supplied electronics.

In order to do this I built a small USB breakout adapter and tried directly connecting this to 5V (for power) and PA11/PA12 (for USB).  The breakout was made by simply soldering some header pins to a USB socket.

I then attached the USB socket to CN12 as shown below.

The complete pinout for CN12 can be found here https://developer.mbed.org/platforms/ST-Nucleo-F746ZG/.

You will need to connect the pins on the usb connector as shown below:

  1. VBUS (+5v)
  2. PA11
  3. PA12
  4. GND

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.