Affordable and flexible platform to ease prototyping using a STM32F401RET6 microcontroller.

Serial pc(SERIAL_TX,SERIAL_RX) problem.

23 May 2014

Hello

I have problem with Serial pc(SERIAL_TX,SERIAL_RX) This is not working on Nucleo.

23 May 2014

@Romik,

can you share the example which is not working? What does "not working" mean? No output? Error message? Serial should be functional.

25 May 2014

I fiound the problem, SB62,SB63 must be on and SB13,SB14 must be remove. All is working.

25 May 2014

I am also not able to get Serial output from the STM32F401 Nucleo board. Are you saying you changed the default solder junctions by removing the zero Ohm resistors from SB13,14 and adding a solder connection or zero Ohm resistor to SB62,63? Is this consistent with the User Manual (I'll check myself)? Can you still use the ST-Link in this configuration. Thanks for any help you can offer as I am new to the Nucleo.

26 May 2014

If you connect SB62,SB63 and remove zero Ohm resistors from SB13,14 Serial pc(SERIAL_TX,SERIAL_RX) will work only via SERIAL_TX,SERIAL_RX and not working via ST-Link. I think that good idea in next version of nucleo add jumpers for that.

17 Jun 2014

If we keep SB13,14 connected and connect SB62, SB63 , Would St-link and arduino comaptiable serial pins both work? In that case data will be same on sT-link virtual com and Serial1.

19 Jun 2014

Sanjay Chopra wrote:

If we keep SB13,14 connected and connect SB62, SB63 , Would St-link and arduino comaptiable serial pins both work? In that case data will be same on sT-link virtual com and Serial1.

I think that this will also relay everything sent/received over the virtual com to the serial link.

20 Jun 2014

yes i checked, i was able to send data correctly but there was some problem in receiving data.

20 Jun 2014

Sanjay Chopra wrote:

yes i checked, i was able to send data correctly but there was some problem in receiving data.

Keeping both sets of bridges connected will effectively short circuit the serial RX/TX on the Arduino connector with the RX/TX pins of the onboard ST-Link interface. Sending data from the target F401 will be ok: both the ST-Link and the external receiver on the Arduino pin will simply receive the same data. When you try to send data to the target F401 the ST-Link transmitter output will fight the external transmitter. One may try to keep the line at High level while the other one tries to pull it low. Not a good idea. This could only work when there are some series protection resistors in the lines. Even then the outputs will compete when you are sending at the same time. I would avoid this solution and use another serial port. In case you really want to do it this way you might try and replace the SB bridges (0 ohms resistor) by an SMD series resistor of say 1K.

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