STM32F407G-DISC1 printf issue

Julien NGUYEN · ‎2021-12-02

Hi there,

I want to do a printf redirected to a Tera Term using the USART2 on the STM32F407G-Disc1, but it doesn't print while the same code works on the NUCLEO-F401RE. I found this instruction in the user manual UM1472. Does it mean that I have to use two flying wires to connect the U2 pins to the P1 connector pins to make it work ? Thanks for your help

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Peter BENSCH · ‎2021-12-02

Please excuse me for not being clear enough: the recent STM32F407G-DISC1 is able to provide VCP if you connect the pins using e.g. flying wires. The solution is only applicable on this newest version, not to the older STM32F4DISCOVERY.
Regards
/Peter

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View solution in original post

Peter BENSCH · ‎2021-12-02

The STM32F407G-DISC1, formerly knows as STM32F4DISCOVERY, still uses an ST-LINK/V2-A that does not yet offer the VCP functionality found in the newer DISCOVERY.

in order to still be able to work with a VCP, you can use the options mentioned in UM1472, section 6.1.3 with the newer STM32F407G-DISC1: either an external USB-UART converter, or the mentioned flying wires.

Good luck!

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/Peter

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Julien NGUYEN · ‎2021-12-02

Hi Peter, thanks for your quick reply ! I still do not understand your suggestion: actually you said I can apply the work around suggested in the UM1742 on the NEWER STM32F407G-DISC1 or on the OLDER ? Thanks, Julien

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Peter BENSCH · ‎2021-12-02

There was an older STM32F4DISCOVERY, and there is a more recent STM32F407G-DISC1, so it depends, what the datecode of your DISCOVERY is. The order designation can definitely be found at the very bottom of the card on the packaging. VCP only works with the newer version, i.e. with STM32F407G-DISC1 only.

Regards

/Peter

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Julien NGUYEN · ‎2021-12-02

Peter, do you mean that with a recent STM32F407G-DISC1, VCP works without the need to connect the pins with the flying wires, it will work like you are using a Nucleo F401RE ? Or did you mean that the wiring solution is only applicable on the new STM32F407G-DISC1 ? Thanks

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Peter BENSCH · ‎2021-12-02

Please excuse me for not being clear enough: the recent STM32F407G-DISC1 is able to provide VCP if you connect the pins using e.g. flying wires. The solution is only applicable on this newest version, not to the older STM32F4DISCOVERY.
Regards
/Peter

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Julien NGUYEN · ‎2021-12-03

Hi Peter. Everything is clear now, thanks for your time.

I was surprised that VCP is not working on the F4 Disco. For me this feature must be mandatory. Even a simple Arduino Uno 10 years dated supports it? Have a nice day. Julien

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