SPDIF out (SBC-i.MX51)

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The i.MX51 is able to output audio signals via the SPDIF line.

See the Hardware User Manual for the location of the SPDIF signal.

1 Linux kernel configuration

Device Drivers  --->
  <*> Sound card support  --->
    <*>   Advanced Linux Sound Architecture  --->
      <*>   OSS Mixer API
      <*>   OSS PCM (digital audio) API
      [*]     OSS PCM (digital audio) API - Include plugin system
      [*]   Support old ALSA API
      [*]   Verbose procfs contents
      [*]   ARM sound devices  --->
        <M>   MXC SPDIF sound card spport

2 Test in Linux

  • Load the appropriate kernel module
root@sbc-imx51:~# modprobe snd-spdif
MXC spdif support initialized
root@sbc-imx51:~# 
  • List available sound cards and PCMs:
root@sbc-imx51:~# aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: imx3stack [imx-3stack], device 0: SGTL5000 SGTL5000-0 []
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: TXRX [MXC SPDIF TX/RX], device 0: MXC_SPDIF [MXC_SPDIF]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
root@sbc-imx51:~# 

You can see that there is a second card "MXC SPDIF".

root@sbc-imx51:~# aplay -L
null
    Discard all samples (playback) or generate zero samples (capture)
default:CARD=imx3stack
    imx-3stack, 
    Default Audio Device
default:CARD=TXRX
    MXC SPDIF TX/RX, MXC_SPDIF
    Default Audio Device
root@sbc-imx51:~#
  • Play sound file on SPDIF:
root@sbc-imx51:~# aplay -D default:CARD=TXRX sample.wav
Playing WAVE 'sample.wav' : Unsigned 8 bit, Rate 8000 Hz, Stereo
root@sbc-imx51:~#
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