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Prajnyajit
Associate III
September 29, 2021
Question

If I remove the SMT32L476RGT6U IC from the Nucleo board first. Then Is it possible to connect SMT32L476RGT6U IC in an external board with STLink pins (CN4) of the Nucleo-L476 (IC is removed) board?

  • September 29, 2021
  • 9 replies
  • 4284 views
  1. If I remove the  SMT32L476RGT6U IC on the Nucleo L476 board.
  2. I will mount the  SMT32L476RGT6U IC on an external PCB.
  3. Now, I will connect the required pins of IC with CN4 of the Nucleo Board.

Is it possible for debugging for external application? My intension is to use STM Nucleo board CN4 to debug instead of one extra STLINK V2 or V3. Is it possible ?

Pin connections will be as follows.

0693W00000FApDzQAL.jpg0693W00000FApEEQA1.jpg

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9 replies

ONadr.1
Senior III
September 29, 2021

Sure. Add board can be cut out and use as STLINK V2. Single MCU can be debugged thru SWDIO and SWCLK pins. If you cut out add board, it is need use internal MCU oscilator or complete external XT oscilator on the board (there are PCB solder points, but not components).

Prajnyajit
Associate III
September 29, 2021

Thank you very much. 0693W00000FApk5QAD.jpgCan you please have an eye on this? Now it is connected with ST-LINK V2, will it work? If yes. I can try it on connecting with the ADD NUCLEO Board (where MCU is cut).

Peter BENSCH
Technical Moderator
September 29, 2021

Yes, of course you can do so. The ST-LINK as part of the NUCLEO-64 can also be broken off / cut off and used as a stand-alone ST-LINK. The only thing missing is the housing.

Good luck!

If the problem is resolved, please mark this topic as answered by selecting Select as best. This will help other users find that answer faster.

/Peter

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Prajnyajit
Associate III
September 29, 2021

Thank you !

Hi, Peter! I have done the schematic of the MCU which is supposed to be mounted on an external PCB. I've mentioned the required connection pins of MCU with an external ST-LINK V2. Can you verify it once and let me know whether it is a go for fabrication or not?

0693W00000FApd4QAD.jpgFirst, let me know whether it is correct or not then we can proceed to the conclusion.

ONadr.1
Senior III
September 29, 2021

I notice, the VDDA/VREF+ is not is not connected. Only blocked by capacitors.

Prajnyajit
Associate III
September 29, 2021

0693W00000FAptWQAT.jpgThank you !

Modified, rest all ok?

Prajnyajit
Associate III
September 29, 2021

NRST is connected to MCURST of ST-LINK V2 and altogether it is grounded. Is it ok?

ONadr.1
Senior III
September 29, 2021

NRST should be connected to VDD via cca 10k rezistor. No capacitor needed. STLINK reset pin is connected direct to NRST MCU pin. If you use ADC convertors, VDDA pin should be connected to VDD via some choke and capacitors.

Prajnyajit
Associate III
September 29, 2021

Now modified. Is it ok?

I have already referred manuals and trying to finalize them. Could you please say is it ok or not? NRST will be connected to the ST-LINK Reset pin when debugging and after the program is loaded it can be connected to VDD with a 10K resistor. Is it ok now?

0693W00000FAqNHQA1.jpg

ONadr.1
Senior III
September 29, 2021

Refer the datasheet, there are more about exernal circuits and connections.

Prajnyajit
Associate III
September 29, 2021

Done and schematic is made. I need a proper verification. Can you help me in this?

Peter BENSCH
Technical Moderator
September 29, 2021

NRST: does not necessarily need a pull-up resistor because a pull-up is already included.

BOOT0: it may be better not to switch the 10k with the switch between GND and VDD, but to connect the 10k resistor directly to GND and, if necessary, to connect BOOT0 to VDD with a NO switch.

HSE: Rext at the 8MHz crystal might not be necessary, please read AN2867, e.g. section 3.5.3. It is also particularly helpful to work through section 3, because the crystal connection is often neglected - it is definiely not enough to simply connect an 8MHz crystal. Section 7 is also very important, especially pictures 11...13, which deal in detail with the correct layout.

Regards

/Peter

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Prajnyajit
Associate III
September 29, 2021

0693W00000FAqjXQAT.jpgI have modified it. But regarding HSE, should I remove this 8MHz crystal oscillator and go?

MM..1
Chief III
September 29, 2021

Last my reply... Your question If i removethe STM IC ... No you dont need remove MCUs from Nucleo boards, but you need handle Nucleo schematics part Default - Reserved jumpers FYI

0693W00000FAumqQAD.jpg Simply in CN2 is on normal Nucleo mode two jumpers and when you remove you can connect external board to CN4...

Prajnyajit
Associate III
September 30, 2021

ok