�?STM32L476RE" --- The cause of the "Failed to read memory" error in the ST-LINK utility

[BMino.1]

Hello

I have created a prototype board using STM32L476RE.

Then I did "Target" > "Connect" in ST-LINK utility, but I got the error as shown in the picture.

I do not know the cause and solution.

 

I did a lot of research on this site and checked the following, but there was no problem.

The power supply is 3.3V to VDD, VDDA is connected to VDD with ChipBias, and has a 0.1uF passcon.

VSSA is connected to GND via a 0805 size 0ohm resistor in the vicinity of VSSA.

I tried to change the "Read Out Protection" from "OptionByte" to Level0, but I couldn't do it. Also, when I select "OptionByte", the display is very slow and appears on the screen after about 5 seconds.

 

I tried to change the "Reset Mode" to "Software System Reset" from "Setting", but I could not change it with an error.

 

What else could be wrong with this phenomenon?

I would appreciate your advice.

[BMino.1]

I tried everything, but even if I programmed the PCROP protection option byte as follows, I got an error and could not write

PCROP1_STRT = 0xffff

PCROP1_END = 0x0

PCROP_RDP = 1 (checked)

PCROP2_STRT = 0xffff

PCROP2_END = 0x0

When we prepared another prototype board for verification, the other board was able to recognize and write data without any problem.

We concluded that the microcontroller on the board in question was probably faulty.

Incidentally, "18mA@3.3V" was always flowing on the empty microcontroller board that seemed to have failed.

I don't know what part of the microcontroller is malfunctioning, but I will proceed with development on a different board.