Smoke came out of the MPU and when I connect it to the computer, the power light is on, but the usb device is not recognized.

[ASONA.1]

I connected the 5v input of usb-ttl to the 5v output of the MPU, while the mpu was plugged into the computer and suddenly smoke came out. Now I get 2.8V from the 5v output of the MPU, 2.5v from the 3v output. Also in the debug circuit, r4,r10,r11,r14 The ,r9 resistors are short-circuited and the d1 diode drops 2.55 volts (this is a bit weird to me).

1) Do you think the mpu can be reused?

2) I couldn't find the resistor and diode values ​​on the board from the schematic. Can I find their values?

[Tesla DeLorean]

1) No, not unless you get the smoke back in. Depends on what components were damaged, and the extent.

2) You've barely identified the MCU, much less the board.

Most of the NUCLEO and DISCO boards have schematics and BOM on the "CAD Resources" tab of the board's home pages.

[ASONA.1]

STM32F407VG MCU.But ı cannot fınd it

[Tesla DeLorean]

You have an STM32F4-DISCOVERY (DISCO/DISC1) board? Or something else? Assume all people known is what you tell them..

https://www.st.com/en/evaluation-tools/stm32f4discovery.html

https://www.st.com/en/evaluation-tools/stm32f4discovery.html#cad-resources

Bill of Materials (BOM) should give component values

[ASONA.1]

Ohh.Thank you very very much

[AScha.3]

>Smoke came out of the MPU

so you got the chance, to see the soul of your cpu going to his grandfathers of the tube area . :))

you get this chance only one time in life (of the chip..) .

now - buy new cpu or better new board, maybe cheaper and 100% working.

+

for not killing the next also, need to know: what you did wrong ?

connect 5v to 3v3 on board ?

[ASONA.1]

I connect 5v to board and same time my mpu is connected my pc

How did I make such a mistake :(((((

I can't buy a new microcontroller because it's too expensive here. I need to get this fixed

[AScha.3]

>it's too expensive here

where are you ? (with actual prices the boards often cheaper than cpu alone.)

what is was your board ? nucleo?

[ASONA.1]

From Turkish.My board is Discovery board(STM32F407VG) Note: 1 Turkish lira=18.85 dollar.:)

[AScha.3]

1. for me still not clear, how you killed the cpu. connecting 5v to 5v would kill nothing. so..?
2. how about your experience in repair ? or capabilities to find the defect ?
3. where did the smoke come from? could you see some defects ?
4. if you killed the onboard STlink (the small F103 chip) , you cannot repair easy.

[ASONA.1]

The MPU was plugged into the computer. The USB-TTL was also plugged into the computer. Then I connected the 5v supply input of the USB-TTL to the 5v output of the MPU. The smoke came out and I disconnected it immediately. Now when I plug the MPU into the computer, the power light is on and from the ,5v and 3v outputs. I am measuring the value. However, there is a short circuit in some diodes and resistors in the debug circuit.

[AScha.3]

so , i looked at the circuit and...if your lucky, you killed only D1 .

test:

• disconnect everything from the board;
• solder small piece of wire to D1, both sides, to bypass it.
• now connect CN1 usb to your PC.
• should see ...stlink.
• and never connect again - whatever you did connect. will kill something ...
• >the 5v input of usb-ttl < is in best case a short to gnd. do not use again !

[ASONA.1]

I will try you said but ı want to ask one more thing. There is a 2.55 voltage drop across D1 diode. Is there any change for this.