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STM32F070 bootloader (on Nucleo board) won't start

Question asked by bassmati on Aug 12, 2016
Latest reply on Oct 7, 2016 by bassmati
Hello everyone,

I am trying to use the bootloader in the system memory of the STM32F070RB on a Nucleo board, but I don't seem to manage to launch it.

After trying several things, here is the state of my board : I removed the MCO and added a 8 MHz crystal. SB12 to 15 are removed, so the debugger should be fully disconnected.

I have a user code in the Flash, that I loaded through the ST-Link interface. This program makes the user LED (LD2) blink in a recognizable pattern. I checked that the 8 MHz crystal oscillates (which it does).

So, to start the bootloader, I checked that the nBOOT1 bit is set to 1. I pull the BOOT0 pin up, and I reset the MCU. I expect to then launch the bootloader, but apparently not : my user code is executing. And a wierd thing happen : the pattern on the LED is ok, but the timing is not (it's slower). It turns out that the crystal does not oscillate, which may explain this (but in this case HSE = HSI = 8 MHz, so I'm not sure about the explanation...).

I've been trying a number of things now, but did not get anywhere. Does this make any sense to you ?

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