STM32F7 Discovery: Encoder Interface & Getting access to PA9

jasonj · ‎2016-11-22

Posted on November 22, 2016 at 21:42

Hello,

I'm trying to get the encoder interface operational on the STM32F7 Discovery Board. Unfortunately, there seems to be a lack-of-pins problem. It seems like the easiest timer to use is TIM1. Channel 1 is on the arduino header, so that's good. However, the second channel is on PA9...which appears to be on the normal micro USB slot.

I'm not using that USB for anything. However, I'm also not able to figure out whether there's something in the way that will mess things up.

Does anyone have experience with getting the encoder interface up and running on this board? I don't want to start with green wire fixes unless I'm 100% they're needed.

#encoder-interface #stm32f7

slimen · ‎2016-11-29

Posted on November 29, 2016 at 16:02

Hello,

You can refer to your reference manual and the datasheet of your product to be able to identify the pins assignment (free/usable pins)

Have a look to this

http://www.st.com/content/ccc/resource/technical/document/application_note/54/0f/67/eb/47/34/45/40/DM00042534.pdf/files/DM00042534.pdf/jcr:content/translations/en.DM00042534.pdf

, it may help you on TIM configuration in encoder mode.

The STM32CubeF7 does not contains an encoder example. So, you can inspire from another STM32Cube package to develop your application, like

http://www.st.com/content/st_com/en/products/embedded-software/mcus-embedded-software/stm32-embedded-software/stm32cube-embedded-software/stm32cubef4.html

which has the ''TIM_Encoder'' example at this path:

STM32Cube_FW_F4_V1.14.0\Projects\STM324xG_EVAL\Examples\TIM\TIM_Encoder

Regards

waclawek.jan · ‎2016-11-29

Posted on November 29, 2016 at 17:00

The F7 Disco, while an impressive demonstrator of the built-in facilities, is a poor general-purpose experimenting platform, as you too have found out. The Nucleos are better in this regard, for the higher-end STM32s.

As far as I can see in the Disco's UM, you have PC6 and PC7 available on the Arduino connector, providing TIM3_CH1 and TIM3_CH2.

JW