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stm32f407, jtag does not respond

Question asked by chappuis.romaine on Jan 2, 2013
Latest reply on Jan 3, 2013 by chappuis.romaine

Hi all,

I have a strange behaviour with 4 stm32f407 boards related to the jtag. The jtag of the stm32f4 is connected to a FTDI4232 chip. I have connected only the JTCK (with a 10k pd), the JTDI (with a 10k pu), the JTDO (with a 10k pu) and the JTMS (with a 10k pu). The NJTRST pin is reconfigured at the reset as the SPI MISO function. To program the FLASH I use an openocd script. Everything worked fine for month and suddenly, I cannot reprogram the FLASH. In my new software release, I use the instruction wfi (when the kernel runs the idle process) and I have reconfigured the GPIO pin handling the NJTRST. Time to time the programming process is operational, but this happens 1 every 10000 tentative :-(

The programming operation is done with boot0 connected at 3.3V and boot1 fixed on the pcb at gnd.

What can I try for recovering again the control of my systems? The silicon revision is A.

Thank you for your advise.

Best regards