STM32H7A3ZIT6Q Custom PCB – ST-LINK/V2 Detects 3.22 V but Shows "No STM32 Target Found"

[Gowri123]

 

Hello STM32 Community,

I am currently working on a custom PCB designed using the STM32H7A3ZIT6Q (Cortex-M7) microcontroller. I am trying to program the MCU using an ST-LINK/V2 debugger through a Tag-Connect adapter, but STM32CubeProgrammer is unable to detect the target MCU.

Hardware configuration:

• MCU: STM32H7A3ZIT6Q (SMPS variant)

• Programmer: ST-LINK/V2

• Adapter: TC2050-ARM20-10 REV2

• Programming cable: TC2050

• PCB programming connector: TC2050-IDC-ND footprint

• External power supply: 3.3 V DC

• Target voltage reported by ST-LINK: 3.22 V

• Debug interface: SWD

STM32CubeProgrammer settings:

• Port: SWD

• Frequency: 100 kHz

• Mode: Under Reset

• Reset Mode: Hardware Reset

• Access Port: 0

• Speed: Reliable

• ST-LINK Firmware: V2J47S7

Error messages:

Error: Unable to get core ID
Error: No STM32 target found!

Troubleshooting performed:

1. The ST-LINK/V2 is successfully detected by STM32CubeProgrammer.

2. The programmer reports a target reference voltage of approximately 3.22 V.

3. The PCB is powered externally using a 3.3 V DC supply.

4. I have verified continuity between the ST-LINK ground and TC2050 connector pin 3.

5. The adapter has configurable GND/+5 V solder bridges. There is currently no continuity between TC2050 pins 3 and 5 on the adapter.

6. The JTAG/SWD schematic includes SWDIO (PA13), SWCLK (PA14), NRST, and GND connections.

7. I previously measured approximately 3.3 V on the VDDLDO supply pins.

8. During power testing, the PCB initially appears to draw current, but the power supply subsequently displays approximately 0.000 A, even though 3.3 V is present.

My questions:

1. What could cause STM32CubeProgrammer to detect the target voltage but fail to read the MCU core ID?

2. Does the STM32H7A3ZIT6Q require any specific SMPS, VCAP, or power configuration before SWD communication is possible?

3. Are there additional hardware connections or voltage measurements that I should verify on a custom STM32H7A3ZIT6Q PCB?

4. Could the TC2050 adapter's unconnected pin 5 GND jumper affect SWD communication, even though pin 3 is grounded?

5. Is there any specific debugging procedure recommended for this MCU when the ST-LINK is detected but the MCU is not recognized?

I would appreciate guidance on identifying whether this is a power-supply configuration issue, a programming-interface connection issue, or a possible MCU hardware problem.

 

[Andrew Neil]

Welcome to the forum.

As it’s a custom PCB, you’ll need to show your schematic.

 

Is it a new design, or have you had this working before?

Have you reviewed the H7 hardware design guide - in particular, power supply arrangements?

 

 

Are you sure your ST-Link is genuine? Does it work with any other targets?

 

https://community.st.com/stm32%2Dmcus%2D60/how%2Dto%2Dsolve%2Dconnection%2Derrors%2Dwhen%2Dconnecting%2Dand%2Dprogramming%2Dthe%2Dstm32%2Dtarget%2Dboard%2D144256

https://community.st.com/stm32%2Dmcus%2D60/how%2Dto%2Dsolve%2Ddebugger%2Dconnection%2Dissues%2D172

 

[mƎALLEm]

Hello ​@Gowri123 and welcome to the ST community,

Need first to refer to the AN5307 “Getting started with STM32H7A3/7B3 line and STM32H7B0 Value line microcontroller hardware development” that recommends to refer to the hardware reference designs Nucleo board (NUCLEO-H7A3ZI-Q) in section 8.

Schematic over here.

[Gowri123]

DIAGRAM OF STM32 AND JTAG

 

[mƎALLEm]

Hello,

Ok you shared the schematic. Did you take the time to review your schematic according to what was shared above?

It seems you are in LDO configuration, the RM indicates this config:

But in your schematic:

VDDSD and VFBSD are connected to VDD!

So please review the RM and the reference design provided above.

[MM..1]

In 1.M author write SMPS variant , then i mean plan isnt LDO…
And on schematics is shown JTAG, but normal STLINK V2 dont use JTAG.

Then start with check power stage, and after this is on connect minimum SWD required wires and setup default speed no 100kHz...