2025-05-02 11:04 AM
Trying to flash F1 and F0 series boards (not a clone, resoldered the MCU with a genuine from mouser) with L4 ST link V2.1, but having no success. Doing the basic CN2 headers out, CN3 VDD(with or without), SWCLK, GND, SWDIO. Spamming every option in CubeProgrammer to talk to the MCU with changing boot settings, doing resets before, while and after connecting, but nothing. L4 talks normally with the internal MCU. I measured MCU - STLink pin to pin resistances, everything seems ok with 22 ohm termination, the only problem i see is when connecting the 3.3V sense to the AIN_1 (CN3 1st pin), then i read in programmer 5.98V (VDD is not 5V, measured, stable 3.3V). In the schematic there is a voltage divider and when 3.3V ST_LINK is there, AIN is 1.65, which goes directly to MCU and shows in Programmer double of that. But by the same meaning, when connecting VDD i bypass with 3V (- schottky diode) and in the programmer get the double. Since its only sense voltage, it shouldnt be neccesary (saw in other posts). After these debugging sessions i thought that the MCU i need to flash is dead, but it isnt, since i connected and flashed with other STLink 2x F103 and F053 boards. the Error is "Error: No STM32 target found!....debug authentication" and in the log there is "unable to get core id" error. So what i should or could do? Thanks.
2025-05-02 11:44 AM
Target voltage 5.98 V is alarming. The target chip is probably damaged and likely dead. Programmer may be fine.
Maybe show your connections and relevant board names. You shouldn't be getting a voltage doubling anywhere.
2025-05-02 12:20 PM - edited 2025-05-02 12:22 PM
Ok, looks like i'm just an overthinker and didn't do the wiggle test roughly enough on an USB cable..... i feel quite silly now, but in the picture it's still visible, that the target voltage is 6V, the question is why shouldn't it be and if so, what else to do about it, since there is only a diode, limiting resistor until it connects to the STLINK MCU? If taking the power from the board then it receives 3.3V_STLINK and AIN pin takes half of it, but for this external sensing i'm putting directly VDD. Can this be considered as a board mistake?