stm32f4 Signal generation

[achourwissem]

Posted on August 22, 2013 at 11:12

hello

i tried the DAC_SignalsGeneration st exemple and i hear nothing , my clock config and all are so fine, so  anyone could give me a simple working code to hear any signal ? and thnx :)

[ran2]

Posted on August 22, 2013 at 12:52

It works fine on my board. Did you press the user button?

[Tesla DeLorean]

Posted on August 22, 2013 at 13:39

Not sure about audio output, I used a scope to test the DAC pins

https://my.st.com/public/STe2ecommunities/mcu/Lists/cortex_mx_stm32/DispForm.aspx?ID=32522&RootFolder=/public/STe2ecommunities/mcu/Lists/cortex_mx_stm32/Help%20with%20simple%20ADC%20on%20STM32F4&Source=https://my.st.com/public/STe2ecommunities/mcu/Lists/cortex_mx_stm32/Flat.aspx?RootFolder%3D%252Fpublic%252FSTe2ecommunities%252Fmcu%252FLists%252Fcortex_mx_stm32%252FHelp%2520with%2520simple%2520ADC%2520on%2520STM32F4%26FolderCTID%3D0x01200200770978C69A1141439FE559EB459D7580009C4E14902C3CDE46A77F0FFD06506F5B%26currentviews%3D247

[frankmeyer9]

Posted on August 22, 2013 at 14:36

... and i hear nothing , ...

 

What do you expect to hear ?

The DAC has an output impedance of about 1 Megaohm w/o buffer amp., and 15 kOhm with amp. That is hardly enough to drive anything passive that creates audible sound.

Use a scope as clive suggested, or attach an appropriate amplifier circuit.

[achourwissem]

Posted on August 22, 2013 at 14:48

thank you so much

anyway that appropriate amplifier circuit could make it audible ? if yes then plz provide me any schématics for that amplifier and thnx

[Tesla DeLorean]

Posted on August 22, 2013 at 16:03

I don't want to wade into this too deeply, but doesn't the F4-Discovery have some of this routed through the codec to the audio jack? I guess you'd want to look at the schematic and demo code to see how that's done, and programmed. May be there are some blog, tutorial or videos on doing it?

[achourwissem]

Posted on August 23, 2013 at 10:03

okay thank you all for advices :)