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sdima1357 / stm32f401cdu6_Audio

low noise low cost stm32 usb-audio dac with optional level meter

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pls answer some question

Aether-yang opened this issue · comments

commented
  1. What is the difference between this git and the following git project?
    https://github.com/sdima1357/stm32f401ccAudioNative
  2. can i connect dircetly to the earphone (resistance about 32R)? PA8 to left earphone and PA9 to right earphone? can it play normly?
    image
  3. Can I use stm32 adc to sample audio (3.5mm lined mic, resistance about 2.2K). any suggestion to the circuit？
commented

1 stm32f401cdu6 and stm32f401ccu6 are not same chips
2 Сan i connect directly to the earphone? - You can't . You hear nothing. Currently output cascade configured in open drain mode.If you put stm32 output in push-pull mode, Stm32 can give only about 20 milliamper and You hear more noise.
3 You can, but you have to add some amplifier to map input signal to 0-3.3v. And you have only 12 bit signal. I suggest You use microphones with i2s output. Google for "Microphone I2S"