i.MX 8M Mini ECSPI DMA Performance Issue – Unexpected TX Gaps

[Woody2]

Hello,

I am experiencing an issue with ECSPI DMA performance on the i.MX 8M Mini when running in master mode.

Issue Summary:

• I set the WML (Watermark Level) to 32, expecting a continuous burst transfer.
• However, instead of a seamless transmission, the TX process consists of 16us of transmission followed by an 8us gap, which repeats continuously.
• When I change WML to 16, the gap reduces to 4us, but burst transmission still does not occur as expected.

Questions:

1. Is this behavior expected due to ECSPI's DMA request timing?
2. Are there any known workarounds or configurations to reduce the gaps and enable more efficient burst transmission?
3. Does adjusting ECSPIx_PERIODREG or BURST_LENGTH help improve DMA performance?
4. Are there any NXP documentation, errata, or other resources related to ECSPI DMA performance tuning on i.MX 8M Mini?

I appreciate any insights or recommendations. Thank you!

 ecspi_master_tx_wml32_gap8us.jpg

[pengyong_zhang]

Hi @Woody2 

There is no way to eliminate this gap, This the HW behavior, We define each word as a frame. You can set the bits per word size to optimize it, But can not eliminate it.

B.R