Arduino for STM32

Thanks for the additional comment - on a different PC it works with only the hal_conf_extra.h so a cache issue does seem possible.
In any case all working now, I appreciate all the comments

I've been programming my projects with Atmel and ESP8266/ESP32 for a while now. I've purchased a WeAct Studio module with an STM32F446RET6. I use Visual Studio Code with PlatformIO and the Arduino framework for programming. I've tried all the UART/USARTs and I've been able to read the signals on ...

it is possible to write directly to flash instead of using EEPROM emulation, these are mostly covered in the FLASH sections of the ref manuals.
The way flash works is that if a page is erased it is reset to 0xff for all bytes, writing data to them toggle the bits to 0.
Hence, it may be possible to ...

think the rx buffer can not hold GPG messages, when the data exceeds 64 characters, exceeded data will lost. You can try code:
String input = Serial1.readStringUntil('\n');

Dear fpiSTM

I read the information you mentioned, I use the Arduino IDE to program the MCU. When I put the file build_opt.h under the project sketch, the compile give the error, say no build_opt.h file. I use a AI assistant and save the file at the 'stm32duno'\libraries\STMCore. It works. But the ...

If you change in the sketch it is not in the scope of the Serial header to redefine it. Sketch is a cpp file.
Use the build_opt.h way as described here:
https://github.com/stm32duino/Arduino_C ... le-content

I am using Arduino IDE to program the STM32F103C8T6. It works. But I can not change the Rx and Tx Buffer size for Seiral1. I know the HardwareSerial.h have the following #defines as:
// NOTE: a "power of 2" buffer size is recommended to dramatically
// optimize all the modulo operations for ring ...

Composite Adding you MCU/board you don't have to configure anything. Some defaults just may need to be set differently.

For example, Serial is usually assigned to PA0/PA1 (for not added MCUs), whereas in STM32duino it usually is assigned to PA9/PA10.
For MCUs with LPUART (like H533RET) you may ...

@Composite All GPIO mappings are done for almost every MCU in STM lineup. For most MCUs you only need to add clock config and sometimes do some changes in default pin assignments (default Serial, IIC, SPI, etc). There are also entries for boards.txt for generic variants, just need to copy them ...

Composite All GPIO mappings are done for almost every MCU in STM lineup. For most MCUs you only need to add clock config and sometimes do some changes in default pin assignments (default Serial, IIC, SPI, etc). There are also entries for boards.txt for generic variants, just need to copy them ...