NUCLEO-H745 + ST-Link Utility = Can not connect to target

[ksamy.1]

We tried our custom board that has STM32H745XI through ST-link V2 with updated firmware. Initially in boot mode the board connects and we were able to read flash. Then after some time the SWD connection is lost.

It is not even able to debug the application. We measured the power supply on CRO and also connectivity with the MCU. We connected SWDIO,SWCLK and ground pins with the stlink.

[Uwe Bonnes]

Does anything eventually remap SWJ pins? Does the application enter Sleep?

[ksamy.1]

Application is also not getting loaded at first.so that may not be the issue.

[Tesla DeLorean]

I'd have thought the NUCLEO-H745ZI-Q would use an ST-LINK/V3

The H7 is very sensitive to the LDO/SMPS and VOS settings in your configuration code. Low power mode and WFI can drop the debug connection due to the circuits involved being turned off. Check also if you change configuration of the PA13/PA14 pins.

When you get invalid settings you need to power cycle the board with BOOT0 High, until you can connect with STM32 Cube Programmer, and then erase the errant code.

[Tesla DeLorean]

Check components and voltages on VCAP pins

[ksamy.1]

The voltage at Vcap is 1.005V and SDC voltge is 1.2V

[Uwe Bonnes]

The asker mentions Nucleo and Custom. I supposed he means custom board and StlinkV2.

[Tesla DeLorean]

Trying to decide if the NUCLEO is just a distraction..

Not really any familiarity with the custom board, potentially design or manufacturing issues there. Not clear what board bring-up checklist items have been met. Would have connected the NRST and SWO too. External ST-LINK/V2 needs to see target voltage.

[ksamy.1]

The CN5 connector on Nucleo-H745ZI is SWD port. I have disconnected the on-board MCU(STM32H745ZI) and connected my custom board at this port so that it can communicate with SLink, but i receive message STM32 target not found even though correct voltages measured at VCAP(1.005V) and 1.2V at SDC

[ksamy.1]

Today i connected the custom board with ST-link/V3. Error "STM32 target not found error" message received.

Measured Voltages: VDD_MCU=3.3V, VDD_LDO=3.3V, V_core=1.005V.

SWD Clk and SWD_IO signal measured on CRO and able to see clock and data. Any further suggestion what could go wrong?

[ksamy.1]

image of error for reference

[Uwe Bonnes]

When going off-board, a speed of 24 MHz may be detrimental. Try with lower speed.

[ksamy.1]

After removing level translator that is used in nucleo board (in swdio and swo lines) and keeping the on-board MCU supply jumpers off, Now we are able to connect the STM32H745XI custom board in boot mode and erase flash successfully. However, we are not able to load firmware or debug in normal boot mode. Any suggestion on this.

[Tesla DeLorean]

Need to cycle power after first code load.

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Check option byte settings.

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I​ would probably start by getting a UART running so I could report on internal state. The work on getting HSE and PLL up.

[ksamy.1]

how to connect stlink v3 of nucleo-h745zi to external stm32H745 custom board?

[ksamy.1]

Finally resolved the problem: if we want to connect the nucleo-H745ZI stlinkV3 to external custom board (STM32H745XI) using CN5, then we need to remove few components that disconnects vdd, smps and ldo supply from main mcu U14(144pins).

Thanks everyone who replied to my queries.