Raspberry Pi Pinout

GPIO 21 (PCM Data-Out)

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PCM DOUTSMI SD13DPI D17I2CSL CESPI1 SCLKGPCLK1
  • Physical/Board pin 40
  • GPIO/BCM pin 21
  • Wiring Pi pin 29

GPIO 21 is used by PCM to provide a data output signal to an external audio device such as a DAC chip.