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Using SPI Bootloader of STM32L476RG

Question asked by Frick.Christian on Dec 9, 2016
Latest reply on Dec 12, 2016 by Frick.Christian

Hi all


I'm trying to use the SPI Bootloader of the STM32L476RG.


To do so, I set up an other STM32 device running an SPI master (Frame Format = Motorola, Data Size = 8 Bits, First Bit = MSB First, Baud Rate = 62.5 KBits/s, CPOL = Low, CPHA = 1 Edge, CRC Calculation = Disable, NSSP Mode = Enabled, NSS Signal Type = Output Hardware). The SPI master is connected to SPI2 of the STM32L476.


I pull the BOOT0 pin to VDD and reset the device. After waiting one seconds, the master sends 0x5A, 0x00, 0x00. The answer is monitored via oscilloscope and is: 0xA5, 0xA5, 0xA5. According to AN4286, the 3rd byte should either be 0x79 or 0x1F. Even if I send additional 0x00's, the device always responses with 0xA5. So it looks like the SPI synchronization is not working properly.


Serving the bootloader with USART worked properly.


What am I doing wrong? Do you have any recommendations?


Thanks a lot