SPI Slave Problem: For STM32L151, If SPI2 is configured as SPI Slave, what is the expected frequency from SPI Master for which STM32L151 can transmit data without any issues?

[Perumal Raj]

STM32L151's AHB is at 32Mhz and APB runs at 16MHz.

Given in the datasheet that SPI Slave clock can be APB clock/2 max.

I have tried to transmit 7 bytes of data from STM32L151. I am able to receive data properly if my SPI master clock is configured to 2.5Mhz. At any higher frequencies, i am seeing data repetition.

For Instance, If I try to send data as 0xA0,0xA1,0xA2,0xA3,0xA4,0xA5,0xA6. I am receiving data as 0xA0,0xA0,0xA0,0xA1,0xA2,0xA2,0xA3 and the transfer is incomplete.

I have tried using polling as well as DMA Mode. Still i face this issue at higher frequency.

I am suspecting that TXE is not set properly during the transaction at high frequency.