SPDIF input possible with colibri IMX8X ?

Technical Support
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1

Hello,

I would like to know if it is possible to use the SPDIF input on a colibri IMX8X or not ?

I followed this : Audio (Linux) | Toradex Developer Center

And in the section NXP/Freescale i.MX 8/8X Family Based Modules, there is a note : This section currently only applies to Apalis iMX8

I should have :

root@apalis-imx8:~# cat /proc/asound/cards
 0 [imxhdmiarc     ]: imx-hdmi-arc - imx-hdmi-arc
                      imx-hdmi-arc
 1 [imxspdif       ]: imx-spdif - imx-spdif
                      imx-spdif
 2 [amixaudiosai   ]: amix-audio-sai - amix-audio-sai
                      amix-audio-sai
 3 [imxaudiohdmitx ]: imx-audio-hdmi- - imx-audio-hdmi-tx
                      imx-audio-hdmi-tx
 4 [apalisimx8qmsgt]: apalis-imx8qm-s - apalis-imx8qm-sgtl5000
                      apalis-imx8qm-sgtl5000

and do this for SPDIF capture :

arecord -D sysdefault:CARD=imxspdif -V mono -c 2 -f S32_LE -r 44100 -t wav spdif_input.wav

But on the colibri imx8x , the cat /proc/asound/cards returns only :

root@kts5colibri:~# cat /proc/asound/cards
0 [imx8qxpsgtl5000]: imx8qxp-sgtl500 - imx8qxp-sgtl5000
                      imx8qxp-sgtl5000

and when I try to record :

root@kts5colibri:~# arecord -D sysdefault:CARD=imxspdif -V mono -c 2 -f S32_LE -r 44100 -t wav spdif_input.wav
ALSA lib ../../alsa-lib-1.2.1.2/src/confmisc.c:767:(parse_card) cannot find card 'imxspdif'
ALSA lib ../../alsa-lib-1.2.1.2/src/conf.c:4660:(_snd_config_evaluate) function snd_func_card_driver returned error: No such device
ALSA lib ../../alsa-lib-1.2.1.2/src/confmisc.c:392:(snd_func_concat) error evaluating strings
ALSA lib ../../alsa-lib-1.2.1.2/src/conf.c:4660:(_snd_config_evaluate) function snd_func_concat returned error: No such device
ALSA lib ../../alsa-lib-1.2.1.2/src/confmisc.c:1246:(snd_func_refer) error evaluating name
ALSA lib ../../alsa-lib-1.2.1.2/src/conf.c:4660:(_snd_config_evaluate) function snd_func_refer returned error: No such device
ALSA lib ../../alsa-lib-1.2.1.2/src/conf.c:5148:(snd_config_expand) Evaluate error: No such device
ALSA lib ../../../alsa-lib-1.2.1.2/src/pcm/pcm.c:2642:(snd_pcm_open_noupdate) Unknown PCM sysdefault:CARD=imxspdif
arecord: main:828: audio open error: No such device

Is it a hardware limitation, or is it possible to enable it by configuring the appropriate recipe / yocto layer to enable SPDIF capture ?
The goal for us is to get a AES/EBU ( SPDIF ) signal and convert and play it on the analog stereo output or on a bluetooth device ( headphone or speaker ).

Regards,

2

I have seen that it is possible to have spdif in with an alternate version of the colibri imx8x :
page 26 : https://docs.toradex.com/105670-colibri-imx8x-datasheet.pdf

pin 50 SPDIF0_TX D34 ADMA.SPDIF0.TX ADMA.MQS.L ADMA.LCD_D11 CONN.ENET1.RGMII_RX_CTL LSIO.GPIO0.IO11 GPIO ALT4 PD VDD_ESAI_SPDIF_3P3
pin 52 SPDIF0_EXT_CLK E35 ADMA.SPDIF0.EXT_CLK ADMA.LCD_D12 CONN.ENET1.REFCLK_125M
_25M LSIO.GPIO0.IO12 GPIO ALT0 PD VDD_ESAI_SPDIF_3P3
pin 74 SPDIF0_RX G31 ADMA.SPDIF0.RX ADMA.MQS.R ADMA.LCD_D10 CONN.ENET1.RGMII_RXD0 LSIO.GPIO0.IO10 GPIO ALT0 PD VDD_ESAI_SPDIF_3P3

But it is shared with LCD , and on my device, I use also LCD RGB output ( for a ortustech 480x800 4p3 LCD screen ).

3

Hello f.mazur,

right the SPDIF pins are also used by the RGB interface.
To see with which module your specific configuration will work, you should check our Pinout designer tool. Pinout Designer | Toradex Developer Center

Best Regards,
Matthias