STM32F030C8T6 GPIO

[ITstreet1]

I designed a board around STM32F03C8T6 in the LQFP48 package. When using a STM32CubeProgrammer, selecting UART I can detect an MCU.

  10:47:20 : RTS low
  10:47:20 : DTR low
  10:47:20 : Serial Port COM13 is successfully opened.
  10:47:20 : Port configuration: parity = even, baudrate = 115200, data-bit = 8,                     stop-bit = 1.0, flow-control = off
  10:47:20 : Activating device: OK
  10:47:20 : Board       : --
  10:47:20 : Chip ID: 0x440 
  10:47:20 : BootLoader protocol version: 3.1
  10:47:21 : UPLOADING OPTION BYTES DATA ...
  10:47:21 :   Bank          : 0x00
  10:47:21 :   Address       : 0x1ffff800
  10:47:21 :   Size          : 16 Bytes
  10:47:22 : UPLOADING ...
  10:47:22 :   Size          : 1024 Bytes
  10:47:22 :   Address       : 0x8000000
  10:47:22 : Read progress:
  10:47:23 : Data read successfully
  10:47:23 : Time elapsed during the read operation is: 00:00:01.132
  10:47:25 : Disconnected from device.

Target info is correct.

I can upload a sketch using a Serial adapter over Arduino IDE. Say Blink sketch.

Sketch uses 11784 bytes (17%) of program storage space. Maximum is 65536 bytes.
Global variables use 892 bytes (10%) of dynamic memory, leaving 7300 bytes for local variables. Maximum is 8192 bytes.
      -------------------------------------------------------------------
                       STM32CubeProgrammer v2.9.0                  
      -------------------------------------------------------------------

Serial Port COM13 is successfully opened.
Port configuration: parity = even, baudrate = 115200, data-bit = 8,
                     stop-bit = 1.0, flow-control = off
Activating device: OK
Board       : --
Chip ID: 0x440 
BootLoader protocol version: 3.1
Device name : STM32F05x/F030x8
Flash size  : 64 KBytes (default)
Device type : MCU
Revision ID : --  
Device CPU  : Cortex-M0



Memory Programming ...
Opening and parsing file: Blink.ino.bin
  File          : Blink.ino.bin
  Size          : 12000 Bytes
  Address       : 0x08000000 


Erasing memory corresponding to segment 0:
Erasing internal memory sectors [0 11]
Download in Progress:


File download complete
Time elapsed during download operation: 00:00:02.090

RUNNING Program ... 
  Address:      : 0x8000000
Start operation achieved successfully

I designed two buttons, Reset and BOOT, and using them I can switch BOOT modes easily.

Now, the problem.
No matter what pin I select to make it blink, there is always float output. Of course, I reset the board after uploading a sketch. Here is a schematic:

I double-checked pins on the microscope. Checked with a multimeter. All looks fine. Battery parts are not soldered at all.

[fpistm]

Hi,

hard to tell.
If I well understand you can flash properly but not output on any GPIO used to blink?

Maybe you end in error handler which could explains why the pin is in its reset state. Clock issue? Power?

[ITstreet1]

If I get an "all ok" message after uploading the sketch, should power, clock, etc, be ok? I will check any suggestions you propose. I can send you links of the components.

I can solder another board, just to eliminate some component issue. But, as I said, on a microscope it looks fine.

[ITstreet1]

I double-check the schematic, in case I connect something wrong.

Now, I am not sure about anything.

[JiriBilek]

Just an idea.
Are you using internal clock or external oscillator in your blink program? I'd suggest to use the internal clock first.
I suppose the bootloader in ROM uses also the internal oscillator so in case your 8MHz osc is not running you won't notice that until you start your program.

[ITstreet1]

No option for that. Or do you suggest unsoldering some of the oscilators?

[fpistm]

OK. I saw your second comment about Serial usage.
Are you sure you are not in Bootloader mode after the flash ? You should check the Option bytes setting, mainly nBoot1

[fpistm]

Just looking the datasheet and it seems you should not use PC13 as OUTPUT to drive a LED:

1. PC13, PC14 and PC15 are supplied through the power switch. Since the switch only sinks a limited amount of current
(3 mA), the use of GPIOs PC13 to PC15 in output mode is limited:
- The speed should not exceed 2 MHz with a maximum load of 30 pF.
- These GPIOs must not be used as current sources (e.g. to drive an LED).

[ITstreet1]

There is no LED soldered. I just measure HIGH and LOW logic with a multimeter. I used any GPIO, the result was the same. No output on any of the GPIOs, and I tried 5-6 of them, random.

With those buttons, I can easily go to Boot mod. While in Boot mode, I can connect to the MCU with STM32CubeProgrammer. When I hit the reset button, I can no longer connect to the chip. So I think it works. When in Boot mode, I can upload sketch using Arduino IDE.

I will try SWD and see if that works.

This about PC13 I didn't know. Glad you point it to me.

[fpistm]

Welcome. Maybe you could also try to get support on the forum. I know some people already design their board.

[ITstreet1]

https://www.stm32duino.com/
Here?

[JiriBilek]

Next, I'd try to disable U(S)ART support in the Arduino IDE. For the blinking sketch you don't need it anyway.

[ITstreet1]

LOL. I disabled U(S)ART and it started blinking...
I have not the slightest idea why is that. Although I have to redesign the board for the built-in LED on another pin. I have to make a few tests just to be sure.

[ITstreet1]

Ok, I made a few tests, it looks fine. All I had to do is to turn off U(S)ART support.

[fpistm]

Anyway this is not normal. Even with U(S)ART support enable this should works.

[ITstreet1]

How does the schematic look to you? Maybe I missed something.

[JiriBilek]

The schematics looks fine for me. In my experience, the STM's processors are quite tolerant as to the voltage or interference.
I have here a STM32030F6 breakout board, I'll try to reproduce the problem.

[fpistm]

As said I'm not an expert. As a first look I would tell it seems OK but can't tell more.
Maybe you can compare with Nucleo schematics.

The only issue I can see if by disabling the U(S)ART it works is that the program use too much RAM leading to error during execution.
I've built the sketch and it seems not the case:

Sketch uses 11832 bytes (18%) of program storage space. Maximum is 65536 bytes.
Global variables use 900 bytes (10%) of dynamic memory, leaving 7292 bytes for local variables. Maximum is 8192 bytes.

So, I have no more idea about this.
Best way would be to debug to see where it stuck.

[ITstreet1]

Can someone change the title? It is STM32F030C8T6

[fpistm]

Can someone change the title? It is STM32F030C8T6

This is already STM32F030C8T6.

[ITstreet1]

Check title.

STM32F03C8T6 GPIO

STM32F030C8T6 GPIO

[fpistm]

done. Missed the '0'

[JiriBilek]

So it's a mystery. I found my old board with STM32F030F6, several times failed to connect the wires correctly (this refers to my statement that STM's survive even bad voltage polarity :) ).
The standard blink sketch works fine for me on PA5.

[fpistm]

Have you tried only with one mcu ?

[JiriBilek]

Fortunately, I have two CPUs here. I'll try the second one tomorrow but I don't expect a change. Will report.

[JiriBilek]

I suspect the question was for the OP not for me. Nevertheless, I tried it with another F030 and unsurprisingly, it worked either.

[fpistm]

Yes it is for @ITstreet1

[ITstreet1]

No, I didn't. A new revision is on its way. It is not easy to solder it and desolder it multiple times. So I will wait a week or two.

[ABOSTM]

I tested my Nucleo F030R8 (closest chipI have in hand).
I used variant Generic F030C8T to be as close as possible to @ITstreet1 setup.
I flashed over UART (PA9/PA10) with boot0 = 3v3 (simple wire)
I used basic/blink example with led built-in on PA5 (and with default menu: USART enabled generic Serial)
And it is working properly: after setting boot0=0V and pressing Reset button, led is blinking.

[ITstreet1]

Haven't tried SWD yet. This is uploaded with UART.

[ITstreet1]

OK.
New PCBs arrived. I soldered everything. I can upload a sketch, and LED blinks on pin PB12.

Now there are a few issues.
Firstly, the schematic is as above with a changed LED pin. There are RESET and BOOT buttons to enter BOOT mode. I noticed I can upload a sketch no matter am I in a BOOT mode or not. Which is weird.
Second, after an upload, it works. But if I cut the power and turn it on again it will not start to blink until I press the RESET button. Which is weird, too.

Any idea what to try?

[ITstreet1]

While taking a closer look, I noticed on Bluepill C9 cap is 1uF, while I used 100nF. Could it be the issue? R3 resistor is 100K, while I used 1K.

I believe there must be a problem.

https://stm32-base.org/assets/pdf/boards/original-schematic-STM32F103C8T6-Blue_Pill.pdf

[JiriBilek]

The capacitor over the reset button is not mandatory, it is used for debouncing the button. The less the value, the less the debouncing effect.

As to the R3, I believe that the value however ridiculously small it is, should not affect the CPU. I have never tried it but I think that you can even short dedicated BOOT pins to GND / VCC.

[ITstreet1]

Let's go over the exam again.

While booting with BOOT HIGH, it should execute the program.
While booting with BOOT LOW, it should go into BOOT mode.

This BOOT mode is what I am not sure about. I double-checked the solder joint on a microscope. It looks ok. I tried to upload a code in both modes and it is uploaded BUT NOT stored in flash. It works until I do not disconnect it from the power. So it is not uploaded in BOOT mode. Why this board doesn't go into BOOT mode? How to check is it in BOOT mode or not?

[ABOSTM]

@ITstreet1 ,
I disagree with your statement:
Program is stored in flash, and after upload, bootloader jumps directly to your application.
But when you power cycle or press reset button, the CPU runs bootloader code (and this is why your application is not running)
So it looks to me like you always run in bootloader first (and eventually after upload, bootloader jumps to application)
After powercycle, you can try to shortcut BOOT0 to GND (bypassing resistor and capacitor) and press reset button, your application should run.

[ITstreet1]

After some intense cleaning with solvents and another check on the microscope, I noticed some of the pins are floating. Not soldered good enough. So I made a few fixes, clean it again, and check the who-knows-what time with a microscope. These are the last conclusions:

-with STM32CubeProgrammer I can see if it is in BOOT mode or not. This part is ok.
-now I can NOT upload a code no matter the BOOT mode with Arduino IDE. Arduino IDE clearly says if it is not in BOOT mode and I can not upload code. If it is in BOOT mode, uploading goes fine. This part is ok.
-after an upload, the board starts executing the program. I don't have to press the RESET button. Is this ok?
-if I upload it, it works. If I press the RESET button while it works, it resets and starts blinking again. This is ok.
-if I power it off and then on, it does not start. I have to press the RESET button. This is not ok.

What to check? What to change?
The upload method is as in the above picture.

[ABOSTM]

-after an upload, the board starts executing the program. I don't have to press the RESET button. Is this ok?

Yes it is ok: at the end of upload, bootloader jumps automatically to application

-if I power it off and then on, it does not start. I have to press the RESET button. This is not ok.

I am not that expert in analog, but my interpretation of this phenomenon would reside in transient level of BOOT0:
When you power up the board the voltage of BOOT0 capacitor will start from 0 and rise to 3,3V. During this rising phase, capacitor will be charging thank to current flowing through Boot0 resistor.
In other words, BOOT0 voltage will start with non 0 value (3,3V ?) and will decrease to 0V.

So what is the sate of BOOT0 when it is evaluated to determined whether to run application or boot loader ? I don't know.

What you can do, for test purpose, is to solder/wire BOOT0 to GND directly, and check if application runs after powerup.

[ITstreet1]

PB6 and PB7 should be SCL and SDA for I2C lines.
https://datasheet.lcsc.com/lcsc/1811061717_STMicroelectronics-STM32F030C8T6_C23922.pdf

Tried U8g2 and Adafruit SSD1306 libs, but no luck.
For Adafruit it trows Serial not declared or so. Could be an issue with disabled USART.
For U8g2, I tried a few from the list for a simple Hello World example. Nothing.

[fpistm]

You have to use a resistor pull up on each lines (typically 4.7K).

[fpistm]

I can upload a sketch with or without U(S)ART support, but it will work only if it is disabled.
This is not normal. Even if U(S)ART support is enabled as it is not used it could not interfere with the blink.

Can I use the Serial terminal just as on Uno? Tried AnalogReadSerial, but get an error while compiling.

Yes the core is fully Arduino API compatible. When you told AnalogReadSerial, I guess you talk about the default example. It works.

// the setup routine runs once when you press reset:
void setup() {
  // initialize serial communication at 9600 bits per second:
  Serial.begin(9600);
}

// the loop routine runs over and over again forever:
void loop() {
  // read the input on analog pin 0:
  int sensorValue = analogRead(A0);
  // print out the value you read:
  Serial.println(sensorValue);
  delay(1);        // delay in between reads for stability
}

In your case for generic STM32F030C8Tx, A0 is PA0:

Arduino_Core_STM32/variants/STM32F0xx/F030C8T/variant_generic.h

Line 18 in 6588dee

#define PA0 PIN_A0

And of course U(S)ART support have to be enabled. using this by default:

Arduino_Core_STM32/variants/STM32F0xx/F030C8T/variant_generic.h

Lines 123 to 135 in 6588dee

	// UART Definitions
	#ifndef SERIAL_UART_INSTANCE
	#define SERIAL_UART_INSTANCE 2
	#endif
	// Default pin used for generic 'Serial' instance
	// Mandatory for Firmata
	#ifndef PIN_SERIAL_RX
	#define PIN_SERIAL_RX PA3
	#endif
	#ifndef PIN_SERIAL_TX
	#define PIN_SERIAL_TX PA2
	#endif

Honestly based on your input it seems your environment is not correct. Maybe install has been corrupted?

[ITstreet1]

For UART
Code will run only when I upload it with disabled Serial. With disabled Serial, code will not compile. With enabled Serial, code will compile and upload, but it will not run.

For I2C
I can not upload the Adafruit example because it uses so many Serial prints. It is all over lib, in Busio too.
U8g2 doesn't work. At least I can not find what instance to use for it.

This project is nothing important. I just have a few of these MCUs, so why not make something with them, and learn along the way.
Maybe someone will need this in the future. :)

[ITstreet1]

BOOM!!!!

Oled works with U8g2.
Pins are PB6 for SCL and PB7 for SDA.
Instance in the lib:
U8G2_SSD1306_128X64_NONAME_F_SW_I2C u8g2(U8G2_R0, /* clock=/ PB6, / data=/ PB7, / reset=*/ U8X8_PIN_NONE);
The screen already has pull-up resistors, so I didn't need them.

USART disabled, of course.

Must try something with SPI.

[fpistm]

Could you share the build errors?

[ITstreet1]

I get errors when building with disabled USART. Which is logical. With enabled USART code will not execute.
If you think for those with disabled USART, it just says Serial is not defined.

[fpistm]

OK. Anyway I've tested and it works as expected.🤨

[ITstreet1]

No idea why I have to disable USART?
Maybe to post this on https://www.stm32duino.com/?

[fpistm]

You can try. Maybe some users will have some more idea.
At this stage, I guess only debug would help to understand why when the U(S)ART is enabled it does not work.

When we met this, it is due a small mcu with not enough flash so enabling it consume much space and explains why it does not run.
Are you sure about the mcu reference?

[ITstreet1]

Sketch uses 8044 bytes (12%) of program storage space. Maximum is 65536 bytes.
Global variables use 552 bytes (6%) of dynamic memory, leaving 7640 bytes for local variables. Maximum is 8192 bytes.
-------------------------------------------------------------------
STM32CubeProgrammer v2.9.0
-------------------------------------------------------------------

Serial Port COM13 is successfully opened.
Port configuration: parity = even, baudrate = 115200, data-bit = 8,
stop-bit = 1.0, flow-control = off
Activating device: OK
Board : --
Chip ID: 0x440
BootLoader protocol version: 3.1
Device name : STM32F05x/F030x8
Flash size : 64 KBytes (default)
Device type : MCU
Revision ID : --
Device CPU : Cortex-M0

Memory Programming ...
Opening and parsing file: Blink.ino.bin
File : Blink.ino.bin
Size : 8256 Bytes
Address : 0x08000000

Erasing memory corresponding to segment 0:
Erasing internal memory sectors [0 8]
Download in Progress:

File download complete
Time elapsed during download operation: 00:00:01.448

RUNNING Program ...
Address: : 0x8000000
Start operation achieved successfully

[ITstreet1]

This blinks the LED.

[ITstreet1]

Sketch uses 11784 bytes (17%) of program storage space. Maximum is 65536 bytes.
Global variables use 892 bytes (10%) of dynamic memory, leaving 7300 bytes for local variables. Maximum is 8192 bytes.
-------------------------------------------------------------------
STM32CubeProgrammer v2.9.0
-------------------------------------------------------------------

Serial Port COM13 is successfully opened.
Port configuration: parity = even, baudrate = 115200, data-bit = 8,
stop-bit = 1.0, flow-control = off
Activating device: OK
Board : --
Chip ID: 0x440
BootLoader protocol version: 3.1
Device name : STM32F05x/F030x8
Flash size : 64 KBytes (default)
Device type : MCU
Revision ID : --
Device CPU : Cortex-M0

Memory Programming ...
Opening and parsing file: Blink.ino.bin
File : Blink.ino.bin
Size : 12000 Bytes
Address : 0x08000000

Erasing memory corresponding to segment 0:
Erasing internal memory sectors [0 11]
Download in Progress:

File download complete
Time elapsed during download operation: 00:00:02.052

RUNNING Program ...
Address: : 0x8000000
Start operation achieved successfully

[ITstreet1]

This is when I turn on USART support: Generic Serial