Does the NRF52840 i2S support TDM? (Using TLV320ADC6140)

[bbaxi]

Recently, I've been evaluating the I2S interface of the 52840 to read ADC data from the TLV320ADC6140 chip.

The TLV320ADC6140 datasheet states that the chip supports TDM mode, but the NRF datasheet only mentions standard I2S mode. Given that the TLV320ADC6140 has four ADC channels, how can I use I2S to read the ADC values ​​from all four channels, instead of just the left and right channel data?

The following is a timing diagram of the TLV320ADC6140 in TDM mode.

Alternatively, could I use the TLV320ADC6140's I2S mode for multi-slot reading? However, NRF's I2S only supports 8-bit, 16-bit, and 24-bit widths. How can I implement multi-slot data reading within a single FSYNC?

[Håkon Alseth]

Hi,

 

nRF52840/nRF5340 has NRF_I2S peripheral, which supports left-justified, right-justified, and I2S mode.

If you require TDM, I would recommend that you look into the nRF54LM20A/B device:

https://docs.nordicsemi.com/bundle/ps_nrf54LM20A/page/tdm.html

 

Please note that the nRF52840 can only do 24 bit width:

https://docs.nordicsemi.com/bundle/ps_nrf52840/page/i2s.html#ariaid-title27

I do not have any experience with this particular ADC, so I am uncertain about the amount of bits it will transfer per word sync.

 

Kind regards,

Håkon

[bbaxi]

Thank you very much for your reply.

It's indeed very disappointing that the 52840 doesn't support TDM, but this has clarified my technical approach.

This ADC is a 4-channel, 32-bit sampling ADC. This means that a single transmission requires 128 bits of synchronization. If the nRF52840 only supports 24 bits, then it's unusable.

I will re-evaluate my solution using the nRF54L.

Thanks again!

[Håkon Alseth]

Hi,

 

bbaxi said:

32-bit sampling ADC.

nRF54L15 can support 32 bit sampling via its NRF_I2S module:

https://docs.nordicsemi.com/bundle/ps_nrf54L15/page/i2s.html#ariaid-title35

 

However, nRF54L15 does not have NRF_TDM. You need to use the nRF54LM20 to get TDM support.

 

Kind regards,

Håkon