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Visitor II
June 25, 2018
Question

read out protection activated on stm32f4 discovery

  • June 25, 2018
  • 1 reply
  • 3880 views
Posted on June 25, 2018 at 13:31

The stm32f4 discovery board I am using has read out protection enabled, and I can't deactivate it.

First of all, it is impossible for me to set read out protection, as the attached screenshot shows, the apply button for option bytes is off-screen and I can't seem to zoom out or do anything with it.

0690X0000060BrZQAU.png0690X0000060BniQAE.png

I certainly didn't set the read out protection to level 1  - it was working fine, and then I unplugged it, and plugged it in about two hours later, and the board simply isn't working. The program isn't running anymore (the USART and SPI should be running, but it isn't).

I think I should mention that a UA741 in an attached circuit caught fire before I disconnected the circuit, but it seemed to be working fine until I disconnected it. The only link between the circuits was a shared ground.

On Keil uVision 5, I get the error 'Flash timeout. reset the target and try again' when I try a flash download.

On the ST Link utility, I get 'Cannot read flash memory! Disable read out protection and retry' when trying to connect to the target.

A possible solution I found online was to set the read out protection to level 0, but that appears impossible.

Any ideas about how I can resolve this?

Thank you in advance.

#stlink #read-out-protection #stm32f4-disovery
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    1 reply

    Graduate II
    June 25, 2018
    Posted on June 25, 2018 at 15:06

    Probably fried the board or chip.

    Check the voltages on the chip side supply, and the voltage on the VCAP capacitors.

    There is a schematic in the manual.

    Try with a substitute board.

    Visitor II
    June 26, 2018
    Posted on June 26, 2018 at 05:47

    Vcap1 and  Vcap 2 are at a steady 1.19V. The voltages on the chip seem normal (about 2.8V on the 3V, about 4.8V on the 5V and about 2.9V on Vdd).