STM32F105 contact with flash through SPI ,the MISO pin has bad waveform

[zli.4]

When MCU（stm32f105） communicates with flash（W25Q64JVSSIQ）, it is found that the waveform of MISO pin is incorrect. Please tell me why this problem occurs。

[Shirley.Ye]

Does the PB14 have the MISO alternate function in F105? why do you using the GPIO_IN_FLOATING mode not the AF_PP mode?

[S.Ma]

MISO is an input. You may have a hw bug or pinout mixup.

[zli.4]

We found the reason. The wrong waveform was generated in the process of erasing FLASH. And the SPI frequency needs to be lowered. If the frequency is increased, the waveform will be normal. If I use the following settings, the erased waveform will have problems。