STM32F407 connection to st-link v2. I have a digital board running code from the external rom that connects to a color LCD panel, switches, and an some switches.

[FLett]

getting Error(4) and Error(7) at various point's in the error logs. USB communication seems to be working and firmware upgrade worked. Logs attached any thoughts?

[Tesla DeLorean]

Don't fiddle with the GPIO or configurations used by the debugger interface.

Don't put the core into a low power state, or cause bus transactions (DMA, etc) which interfere with attempts to wrestle the core into a halted state.

Make sure the debugger can control the NRST pins.

If strapping BOOT0 High makes the problems go away, you're code is doing something unhelpful.

[FLett]

Thanks for looking at this. An excellent clue. Code is running from flash and also making it impossible to halt the core. I incorrectly though st-link would work with anything running from flash.

[Tesla DeLorean]

Running from FLASH should be viable. If the debugger successfully connects to ROM, then it points to something your code is doing to interfere with normal operation.

[FLett]

Interesting, it's a bunch of DSP code, but it uses GPIO pins a bunch. By running from flash I'm thinking external flash. Is there an app note or something that discusses st-link's architecture and signal needs more than the notes I found that discuss cables and LEDs? Thank's for looking at my simple questions.

[waclawek.jan]

Can't this be more result of a hardware problem, like ground loops thrrough the debug cable, inadequate ground/return, too long debug cable, mcu supply problem...?

JW

[FLett]

Super idea. Surprisingly though the little board is really clean for signal integrity stuff though. This time I'm running into my limited understanding of the st-link architecture and an inability to control software very much. The st-link isn't connecting to the target at all. Lately I'm thinking that I need to stop the software at a point when the core quite so JTAG can work. I'm attempting to connect the st-link/v2 to my slightly broken Open_Source software radio .

FL

[waclawek.jan]

> the little board is really clean for signal integrity stuff

You have the STLink onboard?

JW

[FLett]

It isn't at that level of clean, but it is only connected through a 7 cm cable with ground on the cable to the board. "really clean" are famous last words, but I'm certain I'm more fundamentally messed up.

I probably need to get more basic stuff correct, like: target-settings, software's use of GPIO, and core activity. Do you know of a summary sheet for target settings that works for the STM32F407? I think I may have a way of fixing the GPIO and core activity issue. Thanks for looking at my probably simple issue.

FL

[T J]

I don't want to say powersupply

change the cable. change the JTAG dongle.. change computer... change the Ground Lead

dont change the power supply ( :( )

do you have cache turned on ?

[FLett]

Lots of great ideas. I previously didn't state clearly what does and doesn't work, my firmware update works and completes without errors. When I wrote: "it isn't connecting to the target." I meant the target chip target, not the USB dongle target- sorry about that. Anyway, I have some level of confidence in the Windows 10, St link/v2 dongle, cable, and drivers.

Looking at whats working and not working I'm thinking I need to spend more time figuring out how to control the STM32 code I have and the st-link target configuration page.

Thanks a bunch for looking at this thread and making suggestions that illuminated my unclear statement.

FL