May I ask what is the practical purpose for those half complete transmit/receive either for SPI/UART/I2C callbacks?

[Jtron.11]

I would like to understand more the purposes of these half completed callbacks. Are they for monitoring or catch up filling up buffers purpose.

[waclawek.jan]

You are probably taking about the target of DMA half-complete interrupts in Cube (I don't use Cube). These are intended to fill/drain recently handled DMA buffer, while DMA works on the other half. Useful mainly for continuous transfer using the Circular mode of DMA.

JW