STM32L432KBU6TR SPI 16 bit mode issue

[Pinglei]

STM32L432KBU6 L432 chip, spi3, 16bit mode, 20M baud rate, spi output sclk is 16 cycles when it is powered on again after working for a period of time. Sometimes 15 cycles, sometimes 17 cycles, sometimes 16 cycles are output again. This will help confirm the reason， See the following documents for specific applications, thanks a lot. 

[Pinglei]

[mƎALLEm]

Hello @Pinglei ,

First, "STM32L432KBU6TR" as title doesn't mean anything. You need to put a title that gives a raw idea of the subject while keeping it as short as possible. I've edited it to be "STM32L432KBU6TR SPI 16 bit mode issue".

Second, the issue is not clear.

Please review the tips on posting.

[TDK]

Since DR is a 16-bit register, you should be using 16-bit access which is what LL_SPI_TransmitData16 does.

Regardless, I'm surprised that you get this behavior and can't see an obvious cause in the reference manual or errata sheet, which is what I'd expect if DR only supports 16-bit access. On the F4, DR certainly supports 32-bit access. Could be missing something.