RE: How to implement i2s data loopback?

SeanOY — Fri, 18 Dec 2020 06:04:57 GMT

Hi Jørgen,

Thanks! What a detailed answer! What i want to know is the latter you said. 🙂

Best regards,

Sean

RE: How to implement i2s data loopback?

Jørgen Holmefjord — Thu, 17 Dec 2020 09:19:32 GMT

Hi,

The I2S peripheral supports double buffering, allowing you to prepare a new buffer while one is processed. This allows for continuous transfer without any interruptions, which may not be the case if the CPU had to update the buffer pointer at the exact time when one buffer was done transferring. You can read more about this in the EasyDMA chapter in the peripheral documentation.

The I2S example in the SDK is already a loopback example. The SDIN and SDOUT pins are connected together and the data received is checked to be equal to the data transmitted.

Or did you mean that you want to transmit back the data received? In that case, you need to store the received data (in check_rx_data() function) into the next tx_buffer, and configure this buffer for transmit as it is done in prepare_tx_data().

Best regards,
Jørgen