How to power on a STM32H750VBTx bare chip?

[MWeid.2]

Greetings,

I made myself a 100-pin LQFP breakout board and soldered a STM32H750VBT6 to it. I connected all the Vss and all the Vdd. When I try to hook up SWDIO, SWCLK, 3.3V and GND from my ST-Link nothing works. The ST-Link doesn't recognize the microcontroller. The ST-Link itself works tho.

I did the same thing with a STM32L452 and it worked out of the box. I also tried hooking up BOOT0 and NRST to GND but the problem remains. I checked everything, it's very well soldered and there are no short circuits, this is the second chip I tried and it didn't work for both of them.

I placed the chip so that pin 1 is on the bottom left when I can read the text on the chip the right way.

Here is a link to the datasheet: https://www.st.com/resource/en/datasheet/stm32h750ib.pdf

I hooked up pin 10, 19, 26, 49, 74, 99 to GND; pin 11, 21, 27, 50, 75, 100 to 3.3V; pin 72 to SWDIO and pin 76 to SWCLK.

Did I miss something to hook up or do you have any other advice?

Thank you very much in advance!

Here are additional images:

[Uwe Bonnes]

Supply configuration is more complicated. E.g. low ESR amd ESL capacitors are needed on the VCAP pins. Placing these capacitors on the breadboard probably will have high inductance. Have a look at the schematics of a H7 nucleo board to find out what is needed. B.t.w., why didn't you start with a nucleo board?

[MWeid.2]

Thanks for your answer, I'll try looking up the Nucleo schematics.

To your question: Because I like working with bare bone microcontrollers having to do everything myself. Doing it this way it's easier when I have to design a PCB for my project, then I know every single component which is needed. Besides, it's much cheaper.

[AVI-crak]

It won't work like this. Ceramic capacitors 0.1mF + 10nF are required for each pair of VSS / VDD pins - very close to the chip case, 10nF is as close as possible !!! For VCAP line 1mF + 0.1mF + 10nF. For VBAT and VSSA / VDDA, as well as VREF + - 1mF + 10nF is enough.

The STM32H series is not super economical and can uselessly warm the atmosphere with an internal stabilizer. You can bypass excess heating using a pulse voltage converter. The most suitable for this purpose is the MP9148, or two NCP1529 chips (5V-> 3.3V + 1.7V).

Analog peripherals require little current, but stability and low noise are very important (VSSA / VDDA, VREF +). For this power line, a linear regulator powered by the 3.3V-> 3V line MCP1703T-3002E is sufficient.

The main power supply for the debug board is 5V, it can be obtained via usb, or from an external STLINK debugger. It's kind of a standard.

Quartz at 25MHz and 32KHz with load capacitors are required for installation. These elements are very susceptible to external interference, and are not able to work on long wires. External memory on the QSPI interface - it also cannot work on long lines, it makes sense to separate the chip next to the main mic.

Using STM32Hxxx series without JTAG / SWD interface on a debug board is just silly.

[LMI2]

What I remember I think you should connect two pins together, too. Vcap or something. Look at the schematics.

I am not 100% sure you need a crystal, there is an internal oscillator.

Like others, I have used 100nF capacitors between supply pins

It would be interesting to know if your board will work. The CPU can run around 400MHz, so long leads may cause problems.

[LMI2]

Here is my latest version. You should connect Vcaps together.

[TDK]

The problem here is almost certainly the lack of any decoupling or bulk capacitance near the actual chip.

I did not think VCAP pins should be connected together. I never did so on any of my boards, including STM32H7 boards.

But sure enough, this document suggests connecting them on the H7 series:

https://www.st.com/resource/en/application_note/dm00337873-getting-started-with-stm32h74xig-and-stm32h75xig-hardware-development-stmicroelectronics.pdf

[LMI2 · Accepted solution]

VCAP connection is a bit unclear in the documentation in my opinion, I too had them separate at fitst. And the board worked. I "fixed" them when I had other problems and checked everythink once again. That problem was solved when I noticed that ST Link without PC connection holds reset low. I have also voltage of internal regulator low and clock frequency high, those are also not so well documented.