STM32F103 gets stuck inside while (!(CAN1->MSR & 0x1UL));

[MaxYoshida]

Hello

This is amazing, and I have been trying to make it work on STM32F103C8T6 for a month now using this code and other codes as well, but with no success. So I believe it is time now to ask for help.

Issue is simple: I flash the code with Serial.print debugs and it gets stuck inside loop while (!(CAN1->MSR & 0x1UL));

Any ideas what could be wrong? Why is the MSR not set in CAN1->MCR |= 0x1UL; ?

Would really appreciate your support!

[MaxYoshida]

Just to be very clear and avoid possible misunderstandings: I made this modification to the code of STM32F103:

Serial.println("IN1"); CAN1->MCR |= 0x1UL; // Require CAN1 to Initialization mode Serial.println("IN2"); while (!(CAN1->MSR & 0x1UL)); // Wait for Initialization mode Serial.println("IN3");

When running it, on Serial I get both IN1 and IN2, but IN3 is never reached..

[nopnop2002]

Are you using Virtual COM ports?

STM32F103 can use a Virtual COM port. If you enable Virtual COM port, you can use the USB port as a serial port. But Basic Extended CAN(BxCan) and Virtual COM port cannot be used at the same time.

The reason the F103 chip cannot use BxCan and Virtual COM port at the same time is because they share memory buffers.

[MaxYoshida]

I am not sure what you mean exactly. The only modification I did to the code you provided was adding Serial.println commands to see where it gets stuck. I use ST-LINK V2 to upload the code (SWD) and I use a USB TTL converter on pin PA9 and PA10 to get Serial information.

May I suggest that I pay you for a debug session? Name the price and your means of transaction. I am willing to pay for your time on return of getting it working. A lot of things here depend on it!

[nopnop2002]

I use a USB TTL converter on pin PA9 and PA10 to get Serial information.

OK.

I want to know your environment.

• Compile option
• core library version
• the transceiver you are using

[MaxYoshida]

About core library: I always use latest. I have STM32 MCU based boards library by STMelectronics V2.4.0 where the code compiles correctly, and stm32duino V2022.9.26 but the code does not compile in it and it says "CAN1 undefined"

About transceiver, I have MCP2551 module and SN65HVD230 module. Of course when testing I do not mix them up. However, as you noticed, my problem in code is before transmission even begins to happen.

Compile option: I left everything as default from library. Only thing I made sure of is that UART support is enabled and USB support is set to None.

Tell me how to consider the paid debug session?

[nopnop2002]

I use STMelectronics V2.4.0. stm32duino (rogerclarkmelbourne's core) does not support CAN.

This is my compile option.

No problem.

What happens if you run without connecting the CAN Transceiver? Even without a CAN transceiver, the initial processing is finished.

bitrate=4
target_bitrate=500000
ComputeCANTimings result=0
CAN1 initialize ok
Send Fail

I think what's stuck here is a hardware issue.

while (!(CAN1->MSR & 0x1UL)); // Wait for Initialization mode

[MaxYoshida]

I have same compile options.

I tried to remove all hardware (sorry forgot to mention it), issue is the same.

This happens on more than one blue pill. I tried it on 2 of it.

If you believe it is still a hardware issue, I'll buy another 2 or 3 and give it a shot. Again, if this is the problem and it works, I'll be in your debt and pay you for it.

If you think we need a debug session, please tell me. Also, is there anything else you think about? Any other possible issues?

Do you think changing the whole MCU to something else will help? I mean, I can use a different type than a blue pill? It only needs to be cheap, available in like 1M piece in market and has CAN bus, ADC, PWM and fee IO pins.

[nopnop2002]

Is this the same result?

  bool ret = CANInit(CAN_500KBPS, 0);  // CAN_RX mapped to PA11, CAN_TX mapped to PA12
  //bool ret = CANInit(CAN_500KBPS, 2);  // CAN_RX mapped to PB8, CAN_TX mapped to PB9

---

Any other possible issues?

Developing in a clean environment is also an option.

This sample also works on PlatformIO.

If you have an old PC that you no longer use, you can install Linux+PlatformIO on it to develop STM32.

PlatformIO can compile much faster than ArduinoIDE.

---

It only needs to be cheap, available in like 1M piece in market and has CAN bus, ADC, PWM and fee IO pins.

You can use ESP32. ESP32 has CAN bus, ADC, PWM and free IO pins. In addition, it has MAC for WiFi and Ethernet.

This is the time taken to run the same application. ESP32 is more than 5 times faster.

            Float[ms] Int[ms] Clock[MHz]
STM32F103RC 652       17      72
ESP32       95        3       240

[MaxYoshida]

I have tried with CANInit(CAN_500KBPS, 0); It is what I was trying from beginning. Maybe I should try eith pins BP8 ans BP9?

I will check Linux option.

Which esp has can bus? Which model?

[nopnop2002]

I noticed another possibility. Isn't the clone used in your BluePill?

https://hackaday.com/2020/10/22/stm32-clones-the-good-the-bad-and-the-ugly/

Check the chip markings

[nopnop2002]

Which esp has can bus? Which model?

| Supported Targets | ESP32 | ESP32-C3 | ESP32-S2 | ESP32-S3 |

[MaxYoshida]

OMG! Bro, you are amazing. I opened the link, and to my surprise I have the clone shown in 1st picture comparison. Is it possible that I spent a whole month trying with clones..

At this point I have no idea what to do, and how to be sure I am buying original piece and not a clone. I bought these from Amazon Deutschland.

About ESP, yes I heard about ESP-C3. I will give it a shot as well.

But as for now, I am more confident that I have a hardware issue as you pointed, because I am using a clone. Of course I will try to find original one and buy it.

May I ask if you have paypal? I really want to thank you so far

[nopnop2002]

Good to know the cause.

I just noticed, do you have Japanese ancestors?

[MaxYoshida]

You seem not to be very open to paypal idea. So if there is anything I can do for you, just let me know.

Any ideas how to be sure I am buying an original blue pill and not a clone?

I am Japanese by origin. But currently in Germany for work.

[nopnop2002]

I am Japanese by origin.

I am Japanese. I live in Nagoya. But you probably can't display Japanese because you don't have Japanese fonts installed on your PC.

Any ideas how to be sure I am buying an original blue pill and not a clone?

Buy several from different sellers.

---

You seem not to be very open to paypal idea.

This is my hobby, not my business.

---

Digi-key is probably genuine. I think you can buy it in Germany too.

https://www.digikey.de/

[MaxYoshida]

You are right. I only have English and German keyboards here. Besides, I need to work more on my Japanese as the language dies when not used, and I left Osaka when I was 12.

I will take your advice and buy several from different sellers and see how it goes. I will also buy the esp32 as well.

I understand it is a hobby and not business, but at least there could be something I can do for you? Anything?

[nopnop2002]

I understand it is a hobby and not business, but at least there could be something I can do for you? Anything?

teach me german :)

Or how to cook a delicious sausage :)

[MaxYoshida]

About German, I'd absolutely do that. We can have online sessions and I'll do it if this is what you want. About cooking sausage, not something I can help with. I am vegetarian..

Hey, how about we talk using whatsapp? If you are open for it of course..

My number can be found inside this link: https://docs.google.com/document/d/1G0gJc9-uuI-XFvCi97k06_Ib1Zad2vJHtIrokvYT-P0/edit?usp=drivesdk

I'll delete it once you see it. If you are not interested, then I apologize and you can just ignore it

[nopnop2002]

Unfortunately I can't have a conversation in English.

Same as most of Japanese.

This document was written using Google Translate.

[MaxYoshida]

Demo, nihongo o tsukatte mo ī ndesu yo. Rōma ji de kaku to

[nopnop2002]

Demo, nihongo o tsukatte mo ī ndesu yo. Rōma ji de kaku to

Thnak you,

I will close this issue.

You can RE-OPEN at any time.

[dartrax]

I noticed another possibility. Isn't the clone used in your BluePill?

https://hackaday.com/2020/10/22/stm32-clones-the-good-the-bad-and-the-ugly/

Check the chip markings

Thanks for mentioning this. I had the same problem. But while my bluepill looks genuine, after further inspection I'm convinced that it's a fake without CAN functionality.

[nopnop2002]

@dartrax

I'm glad you found the cause.

[nopnop2002]

@dartrax

after further inspection I'm convinced that it's a fake without CAN functionality.

If you have time, it would be helpful for others if you could publish how to determine if it's a clone.

[dartrax]

I used https://mecrisp-stellaris-folkdoc.sourceforge.io/bluepill-diagnostics-v1.6.html It showed it was a clone. That alone might not mean that CAN doesn't work. But I rechecked the reviews of the shop where I bought it and I found at least one which confirmed that CAN functionality was missing. I also tried other libraries which failed at the same spot. Now I've got an STM32F072 so I'll try with that since I read that nearly all available Bluepills are fake now ;-)

[nopnop2002]

@dartrax Thank you for report.

Your report will help us to identify whether it is a clone or not.

since I read that nearly all available Bluepills are fake now

Oh my God.