Stm32f29 swd problem

[arunnmishra]

Posted on April 19, 2014 at 16:52

Hi there,

I've designed a board on stm32f407zgt6 earlier and succeeded to connect my board with st link. All SWD connections were directly taken out from controller with no external pull-ups or pull-downs. Now again I've designed a board on stm32f429igt6 (176 pin package). On this board I've successfully programmed my code once. But after that I could not connect my board with st-link anymore. I'd also tried with new boards and new controllers but failed in doing so. I am using on board st-link debugger (one which comes with discovery boards).

Boot0 pin is directly ground (I've also tried to pull it down through 1k resistor) Boot1 is floating. Any kind of help/suggestion will be appreciated.

Thanks

#st-link-not-connected-stm32f4

[Tesla DeLorean]

Posted on April 19, 2014 at 17:50

If the code you put in there is broken (WFI, low-power, etc), then you'd need to get BOOT0 HIGH to run the System Loader code to provide a safe harbour from which to re-flash it.

[arunnmishra]

Posted on April 21, 2014 at 10:00

Thanks clive1, I've tried your suggestion of pulling boot0 high(boot1 low) but again it worked once or twice. One thing to mention here that i am using st-link firmware update V2.J17.S0 (which i guess is OK). I'm not even programming the board, just reading the code area. I'm very confuse why after one-two attempt i am failing to connect my boards (till now i've tried with three boards and three controllers). Do you have any idea/suggestion related to this issue. Does performing life of sign test will indicate some issues.

Thanks

[arunnmishra]

Posted on April 21, 2014 at 14:52

Hi clive1,

I got something extra which might help you analyzing the problem. Now what I am observing is that when I remove the tiny capacitor (100nf ) from reset pin and try to connect the board under reset, it gets connected. However I am still unable to download my hex into the controller. Under reset my board is connected at either status of boot0 pin. If you have some suggestion/solution please let me know.

Thanks

 

[Tesla DeLorean]

Posted on April 21, 2014 at 15:31

I got something extra which might help you analyzing the problem.

Perhaps you can find me a schematic too?

Poor reset circuits can cause many problems, make sure the analogue supplies are connected, that you get 1.25V at the VCAP pins, and NRST is connected to your SWD connector.

[arunnmishra]

Posted on April 22, 2014 at 08:03

Hi clive1,

Though I've solved the problem by removing the capacitor on reset pin and programming it under reset but still i want to know why i've to do this. I'm attaching my schematic for your reference

Thanks

________________

Attachments :

SCHEMATIC1___Controller_176.pdf : https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006I0QI&d=%2Fa%2F0X0000000beC%2FSNL0Vw98nQjJGtAuAHpQT1aul_TWNnMSJL5oCIdGrtw&asPdf=false