topic LPC 55S28 I2S DMA Send in LPC Microcontrollers

LPC 55S28 I2S DMA Send

MHY_0878 — Wed, 05 Mar 2025 09:00:40 GMT

Hi guys, I am generating 16-bit and 24-bit positive sine wave in MCU lpc55S28 for testing, using I2S and DMA to transmit 16-bit positive sine wave data is normal, but transmitting 24-bit positive sine wave data, only the I2S transmission waveform is correct, DMA transmission waveform is abnormal, I don't know what the reason is, please help me.
Attach my project code at the end.

Re: LPC 55S28 I2S DMA Send

Harry_Zhang — Fri, 07 Mar 2025 07:09:10 GMT

Hi @MHY_0878

I checked the i2s DMA code,

bytesPerFrame is determined based on the width of i2s, so there is no need to modify it.

"the DMA transmission waveform is abnormal"

How do you test DMA waveforms? Can you send photos of the relevant waveforms?

Harry

Re: LPC 55S28 I2S DMA Send

MHY_0878 — Fri, 07 Mar 2025 13:01:18 GMT

Hello, first of all, thank you for your reply, the problem has been found so far, it has been solved.