Arduino for STM32

oops , right

thank you ozcar
1) my project will light 8 RGB chips every 100ms ; the whole duration for one transmission is ~2us , so there is no problem to use a blocking little piece of code , but yes , I hate this way to do
2) SPI and DMA are , with GPIO , the simplest peripherals in a STM32 , so they are easy ...

I made some tests with cubeMx and cubeIDE (fast compile and upload , easy debug) :
NSS , MISO and even SCK pins can be reused as GPIOs , or ADC inputs , but not for the timer peripherals (contrary to cubeMx)

still hoping for some help in order to make DMA→SPI→WS2812B

Hi fpiSTM , thanks !
I will try
here is my code about SPI→WS2812B
I use 3 SPI bits to make 1 RGB bit ; the duration of 1 RGB bit must be ~1.26us , so the duration of each SPI bit = 0.42us
For the STM32F103 @72MHz , I have set the SPI prescaler at /32 , so the duration of 1 SPI bit is 32/72 = 0.444us ...

Hi All,
my problem here is BLUE.PILL→DMA→SPI ; I have done it successfully with CubeIDE (HAL) , but now I have to import this to STM32duino , and I am afraid of this
Probably some of you did the trick , or are able to give me some important advices , so thank you !

ok , I will try something different :
1) instead of configure the two pins , for exemple : HardwareSerial Serial1(PA10, PA9);
just configure the Tx pin : HardwareSerial Serial1(PA9);
this will configure USART1 as half-duplex single wire mode , on PA9 = Tx pin ; at this point , PA9 is high Z , so ...

Hi fpiSTM , thanks !
I have tried to to declare first the the Rx and Tx pins , as STM32duino wants , and then make the Tx pin an input ; this works , but for a short moment , the Tx pin will be OUTPUT : HIGH , in conflict with the output of the device it is connected to , so this is not an option ...

STM32 , from the beginning , can do Rx or Tx alone , and the other pin can be used for another purpose
( I have being playing with STM32 a looong time before STM32duino )
some of the features of the USARTs (from the reference manual of your G431, a very interesting document ! ) :
• Separate enable ...

what I want to do , all USARTs Rx only :
USART3 Rx = PB11
LPUART1 Rx = PB10
USART2 Rx = PA15
USART1 Rx = PA10
UART4 Rx = PC11

oh yes , sorry , you have pointed the right thing :
the sketch with USART3 works , printing the registers to be sure :
USART3->CR1 : 45
LPUART1->CR1 : 0
my problem is actually that I only want the USART to work as a receiver ; Tx pin will be used for another task
so if I declare :
HardwareSerial ...