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FCamp.1
Graduate
January 15, 2023
Solved

STM32H723 Custom Board - St-Link V2 very slow

  • January 15, 2023
  • 2 replies
  • 1632 views

Hello,

After prototyping with a Nucleo H7 board, I'm setting now up a custom board with a STM32H723ZGT6 MCU (the same MCU present on the Nucleo).

I connected my USB Dongle ST-Link V2 via SWD to program the MCU and after having struggled a bit, I have finally come to a working setup but with quite slow frequency 100 Khz as solution. Increasing the frequency leads to impossibility to erase, to download my program or sometime to generate inconsistency errors between what is downloaded and the original code.

At 100Khz debugging is a bit of a challenge so i need to speed it up if possible.

Anyway what is stressing me is that I don't understand if that's normal or not...

In terms of the SWD my setup is: SWDCLK and SWDIO connected directly to the dongle, RST connected with a 10k resistor between the dongle and the MCU, gnd and VDD connected to 3.3V on the board.

The St-Link V2 dongle framework is updated to last version.

Config of SWD is:

1) frequency 100

2) mode Normal

3) Access point 0

4) Reset mode Hardware Reset

5) Speed reliable (if I set fast again I fall into the very same above described issues)

In terms of the MCU power setup I set:

1) all VDD decoupled with 100nf cap

2) VREF decoupled with 1uf and 100nf caps in parallel (as per Nucleo schema)

3) both VCAP (which I don't use cause i use the internal regulator) decoupled with 2 2.2uf caps in parallel (as per Nucleo schema)

4) PDR_ON connected to vdd with 10K resistor (as per Nucleo schema)

5) BOOT0 connected to VSS (i let the dongle switch to the system memory for the programing action and switch back after reset)

is there anyone that can help me in understand?

I was thinking to buy a St-Link V3 Set but unfortunately in this moment speculation is crazy and the prices requested are simply ridiculous...

Thanks a lot in advance,

Filippo

    This topic has been closed for replies.
    Best answer by FCamp.1

    UPDATE: I think it's in fact a noise problem.

    I checked with the oscilloscope on the power rails and I can clearly see a recurrent spike variable in intensity but sometime quite huge which i think is the problem.

    I made some filtering and finally I arrived now at 949 Khz frequency which i think it's still quite slow but is anyway acceptable. I will keep on trying to set some more filter and i will try also with V3 to see if anything changes.

    Cheers,

    Filippo

    2 replies

    M
    MM..1
    Graduate II
    January 15, 2023

    At 100Khz ISNT normal your schematics (show part stlink) or PCB quality is bad

    too connect RST over 10k is for what?

    And last extreme 5) BOOT0 connected to VSS (i let the dongle switch to the system memory for the programing action and switch back after reset) ???

    Plus if you have Nucleo board you can use onboard STLinkV3 with your board ...

    F
    FCamp.1Author
    Graduate
    January 15, 2023

    Hello,

    thanks for answering.

    There is no 10k resistor, I made a mistake. I put instead a decoup cap for 100nf as per Nucleo schematics.

    About BOOT what i meant is that i keep it in VSS in order to boot from 0x08000000 always.

    Cheers,

    Filippo

    F
    FCamp.1AuthorAnswer
    Graduate
    January 15, 2023

    UPDATE: I think it's in fact a noise problem.

    I checked with the oscilloscope on the power rails and I can clearly see a recurrent spike variable in intensity but sometime quite huge which i think is the problem.

    I made some filtering and finally I arrived now at 949 Khz frequency which i think it's still quite slow but is anyway acceptable. I will keep on trying to set some more filter and i will try also with V3 to see if anything changes.

    Cheers,

    Filippo

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