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Sashvat
Associate III
June 13, 2019
Question

Is my circuit for building a MC board fine?

  • June 13, 2019
  • 9 replies
  • 5009 views

Hi guys, I have built this STM32F334K4T6 MC dev board, I want to know if the schematic and the PCB wiring are all fine.

I also would want to know if the board will power on and will I be able to upload code to it and see an LED blink or so. I have attached the schematic and the PCB I have made. I haven't added the ground copper layer yet, its so that you can see my wiring and give it a go to send it to the fab house.

Thank you

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9 replies

Uwe Bonnes
Chief
June 13, 2019

You should connect 100 nF from NRST to ground.

You should connect VDDA, do not leave any supply pin open.

You PCB image does not show fill. C1 and C2 ground path is not short. Rotating C1/3 180 degree will close ground path much shorted.

C3/C4 don't need to be close to the device, Eventually one part is enough for all pins. Consider a bigger size so that effective capacitance at 3.3 Volt is higher.

But for a first test. consider a F334 Disco boards...

Sashvat
SashvatAuthor
Associate III
June 13, 2019

As I said, I havent filled the board with the ground copper yet, but have done it. And regarding VDDA, should I directly connect it to VDD? And for the NRST, there's a specified reset circuit the data sheer shows, do I follow that and I haven't added a NRST button

Tesla DeLorean
Guru
June 13, 2019

Pull down on BOOT0, or jumper so you can pull up/down

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Sashvat
SashvatAuthor
Associate III
June 13, 2019

Sure thank you, but what is the use of this BOOT0?

Tesla DeLorean
Guru
June 13, 2019

It you let BOOT0 float, and your supply rises slowly, there is a strong probability it will be determine to be HIGHish, and the code in ROM will run instead of your code in FLASH.

Long list of forum participants that have failed to do this properly.

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Uwe Bonnes
Chief
June 13, 2019

What about taking a look at the reference manual? Figure 23. Recommended NRST pin protection clearly shows 100 nF at NRST. It is needed for reset timing. Find BOOT0 also in the reference manual ans in an2606

Sashvat
SashvatAuthor
Associate III
June 13, 2019

Some people told me a NRST push button is not required, should I put it on my schematic?

Uwe Bonnes
Chief
June 13, 2019

Fig 23 shows a pushbutton _and_ a capacitor. To place a pushbutton or not is your decision. I feel it is handy to have a rest pushbuttom. For boot, look at datasheet 3.2.3 3.2.3 Boot modes

     At startup, BOOT0 pin and BOOT1 option bit are used to select one of three boot options:

         

Sashvat
SashvatAuthor
Associate III
June 13, 2019

But I don't see a BOOT1 in the schematic at all, where is it?

Uwe Bonnes
Chief
June 13, 2019

But I strongly suggest that you get a F334 Discovery first. Then you have something known good to start with. When you have climbed the learning curev, start designing your own boards. Otherwise sources of possible errors are endles...

Sashvat
SashvatAuthor
Associate III
June 13, 2019

is the nucleo 32 also a good board to start out with?

Uwe Bonnes
Chief
June 13, 2019

It is "BOOT1 option bit ". Read 3.2.3 Boot modes again!

Sashvat
SashvatAuthor
Associate III
June 13, 2019

ohh I am sorry. Thank you for your help. and I had asked, is the STM32-nucleo board good to start with? or the discovery boards? And can I program either of these boards using Atollic True Studio?

andy2399
Senior
June 13, 2019

In low pin count microcontrollers, the BOOT1 pin is only available as a programmable fuse.

You don't need to worry about BOOT1 but if you want to bootload code using one of the serial interfaces you need to control BOOT0.

Typically, you want to pull BOOT0 to ground with a jumper or switch to VDD. When BOOT0 is pulled to VDD, the bootloader mode is entered.

See the table in section 2.5 of the reference manual.

Andy

Piranha
Principal III
June 14, 2019

Why are so many people ignoring "Getting started with STM32xx series hardware development" series application notes? Read the AN4206!

A "development board" without debugging... And why make development board at all? These are the ones You want to buy. Custom product boards are the thing You will have to design by Yourself. Just take some STM32 Nucleo board and learn software development on that - that's what is the most important thing!

Sashvat
SashvatAuthor
Associate III
June 14, 2019

Is this a book that you are talking about or a document that is available? And thank you for that advice, I am buying an STM32 Nucleo-32 board and starting to program it, but is that a book? Where can I buy it?

Sashvat
SashvatAuthor
Associate III
June 14, 2019

But no one has told me if it works or not? will it work? can I upload code and make it do some task?

Piranha
Principal III
June 14, 2019

At the state it's shown, definitely no.

Sashvat
SashvatAuthor
Associate III
June 15, 2019

Then can you please tell me what to fix? I can send you the updated schematic I have done