Problem to connect to STM32F407E (ST-Link)

[flyer31]

Posted on May 18, 2012 at 13:39

Hi,

we produced a small demo board with STM32F407E, but we could not connect to STM32F407E (100pin LPC with 512k memory) - a previous similar board with the 144pin version worked without problem. Next we will try the STM32F407V (100pinLPC with 1M memory). Anybody else here, who had difficulties with STM32F407E?

[alok472]

Posted on May 19, 2012 at 06:50

Are you using ST-Link or STLINKv2 ?

pls specify if you are using SWD mode or JTAG ? Did you check reset signal and continuity between different signals ?

[flyer31]

Posted on May 19, 2012 at 13:39

I use the ST-Link-Interface of ST4Discovery (Jumper CN3 open, and 4-line connect to CN2: GND, NRST, SWDIO, SWDCLK). - According to ST4Discovery, this is the ST-Link/V2 interface, which is implemented on ST4Discovery. I use SWD interface.

Concerning NRST signal: we have two new boards here. On one board NRST quite immediately switches nicely to 3.3V. On the other board, it keeps hanging at 0.3V, if nothing connected, and if we connect the debug adapter, it switches only to 2.9V. (which I think is a bad sign, if I read other posts here in the forum). Strangely the ''nicer'' board (concerning NRST line) is the much more complex one, with also quite a bit 5V interfacing (but we were careful to put it only to 5V compliant pins). The ''bad'' board is a very simple board with only debug interface and ULPI interface for Hi-Speed USB connected ... . The ''bad'' board has a bit less capacitors (just exactly the caps required by STM - but STM32F4discovery also is on this level, and STM32F4discovery of course is working nicely). Both boards are in ''virgin'' state - we did not succeed to establish communication yet (we tried Keil with ST-Link-SWD debug + flash programming setting, and we also tried the STM32 ST-Link Utility software. This shows the error message ''Internal command error'' (so it somehow recognizes, that a target is connected, as without debug adapter connected it shows the error ''No target connected''). With our 144pin test board, all runs nicely. We currently only have the A version chips here (100pin and 144pin). For the 2 problem boards with the 100pin chips, we tried already to put the PDR_ON pin to 3.3V, but this did not improve the situation. We now ordered 3  further 100pin different chips from mouser, I hope one of them might be Z version, as on STM32F4discovery board. (STM32F4discovery of course also running without any problems ....). Really strange. PS: I just recognized, that some of our STM32F4discovery boards have the A version STM32F407V ... so our initial suspect that it might be a problem of the A version can be ruled out ... now I am even more puzzled.

[flyer31]

Posted on May 21, 2012 at 14:10

Now I think we got it: We have to reduce the power supply from 3.3V to 3.0V. Then all works nicely

I made a new thread, as I think this is some more general question ... .