STM32F4 - Discovery fail

[regiuliano2009]

Posted on February 17, 2012 at 11:44

Dear

STe2e Community,

I'm newbie to STM32F4 programming so I'm starting using a Discovery Board. I'm searching to get working a led on/off circuit with power terminal of the board but I don't know I burned 2 discovery board. I mean that the ST-LINK is not responding and LD8 is red. In the other board also LD5 is red. Is there any procedure to make these boards start working again or I wasted my money?

Thx to everyone for the replays.

CX3

#me-too

[Tesla DeLorean]

Posted on February 17, 2012 at 13:53

If you managed to brick the board, you can strap the BOOT pin to 3V3, and restart it, to recover.

[regiuliano2009]

Posted on February 17, 2012 at 14:41

Thx clive1,

I tried to reboot as you said but the discovery wasn't bricked, I think it's FUSED (!).

Also, Windows said that the Usb (ST-LINK) isn't recognized.

[Nickname12657_O]

Posted on February 17, 2012 at 14:49

Hi,

I need to know if your STLink driver is well installed on your machine and when connection the discovery board, if the PC will detect the STLink?

Else please refer to

http://www.st.com/internet/evalboard/product/251168.jsp

  Design support and re-install the STLink driver.

Cheers,

STOne-32 

[regiuliano2009]

Posted on February 17, 2012 at 14:59

Dear ,

my ST_LINK is installed and it's working properly. The board and ST_LINK stopped working (LED8 reddish and LD2 red) when I mounted an external LED between 3V e GND external pins of the board. I made a mistake wiring it directly and not through a resistor.

[Tesla DeLorean]

Posted on February 17, 2012 at 15:28

I think it's FUSED (!).

Not much you can do to fix evaporated silicon, best to design and evaluate the added circuits more carefully.

[regiuliano2009]

Posted on February 17, 2012 at 15:46

eheheh you are right!

But I don't think the micro go off, I think the Discovery is gone out. I can't figure that isn't any current protection on Vdd short-circuit! Also the Discovery is USB powered... how many mA can put out? Only a few...

[regiuliano2009]

Posted on February 17, 2012 at 16:23

I discovered that the micro is still working because I powered the board via external power supply. So is the ST_LINK death. Looking at the manual of discovery (pg 16) the 5V power supply must have a power consumption below 100mA so isn't any current protection on power supply, I guess...

[Nickname12657_O]

Posted on February 17, 2012 at 17:10

Hi,

you can try this test:

1- download and install the DFU

http://www.st.com/internet/com/SOFTWARE_RESOURCES/SW_COMPONENT/SW_DEMO/um0412.zip

2- connect an USB cable between your PC and CN5 on the discovery board,

3- connect Boot0 pin to VDD.

4- press reset

==> Then, if your micro is still surviving, you can download, upload ... images to/from flash...

Then you can confirm if your problem is comming from the STlink or not !!

Cheers,

STOne-32

[donald2]

Posted on February 18, 2012 at 08:19

We had an unprovoked failure of a F4 Discovery.

It happened at a bad time, as we *really* needed the STLink to work and it was the only one we had.  So we tracked down the problems.

I suspect that it was caused by a failure of the USB power switch that shorted 5V to the 3.3V rail. Whatever the actual cause, the power switch was the initial hot spot, and it had a near zero resistance to ground. Once we removed the power switch, we found that the audio chip was drawing most of the power.  We isolated that by cutting traces.  At that point the board mostly worked, but the 3.3V regulator quickly went into thermal shut down.

It was the only source of heat at that point, even when we powered the board with 3.3V, so we removed it from the board.  We found that it was bad, so we swapped the 2.5V regulator in its place.  We don't have SOT23-5 regulators around, and the 2.5V regulator wasn't used with the audio cut out of the circuit.

The board now works fine, both the STLink and STM32F4 portions, with no abnormal current draw.  The micro-USB or audio portions are dead, but we weren't using those anyway.

[regiuliano2009]

Posted on February 20, 2012 at 12:40

thanks STone e Donald,

by the Donald's experience I started to investigate the problem by an electrical level. When the board is USB powered I have in Vin_U1 a voltage of 2,4V and in Vout_U1 2,4V and the regulator isn't working. I looked at D1 and it has a voltage drop of 2,4V on him (!!! I think it's abnormal... do you think?).

So I power on the circuit by an external power supply, (As I said before the F4 was still working) and I started to look at the voltages around the circuit. U1 is working good 5->3,3, D3 3,3->3 ad D1 is off. Good.

So, I attached my USB cable CN1 and ST-Link started working again!!!!!!!!!!!!!!!! O_o

So, I'm asking you which is the problem with my boards. Is D1 the problem? Like Donald, I think that I have touched 5V with 3V external pin in my first board.

thank you again