2416689_en-US

S32K3 SAI TDM problem

Hi, NXP expert
I'd like to ask about the S32K322 chip. What is the maximum supported block size for the SAI interface TDM? Is it frame size × width?
That is, 16 × 32 bits = 512 bits, or 64 bytes?
Thanks!

Re: S32K3 SAI TDM问题

Hi @Chenxu1

You must also consider the maximum supported bit clock (BCLK) rate of 12.288 MHz. For example:

TDM8, 16-bit, 48 kHz → BCLK = 8 × 16 × 48,000 = 6.144 MHz < 12.288 MHz (Supported)
TDM16, 16-bit, 48 kHz → BCLK = 16 × 16 × 48,000 = 12.288 MHz (Supported at the limit)
TDM16, 32-bit, 48 kHz → BCLK = 16 × 32 × 48,000 = 24.576 MHz > 12.288 MHz (Not supported)

Therefore, a configuration of 16 words × 32 bits = 512 bits (64 bytes) represents the theoretical maximum frame size supported by the hardware. However, the practical configuration is also limited by the maximum supported BCLK rate.

BR, VaneB

Re: S32K3 SAI TDM问题

Hi，thanks for your reply.
I mean, does the TDM DMA buffer have a length limit? 1024bytes？

Re: S32K3 SAI TDM问题

Hi @Chenxu1

DMA transfers are limited by the DMA Major Loop Count implementation. Due to the CITER[14:0] the number of bytes transferred in a single DMA transaction must be less than 32,767 bytes.