UART1 and UART2

[workpage2]

I am using a Blackpill 411CE board. I use generic F411CEUx in chip configuration.
To configure uart, I use the command:
Serial.begin(115200);
and
Serial2.begin(115200);
However, data exchange in both cases goes through PA2 and PA3.
How do I switch to PA9 and PA10?

[fpistm]

Hi @workpage2
First, please use the forum or the GH discussion to request support.

Generic F411CE define the Serial2 with PA2/PA3 by default, Serial is mapped on Serial2.

Arduino_Core_STM32/variants/STM32F4xx/F411C(C-E)(U-Y)/variant_generic.h

Lines 128 to 140 in 975da6c

	// 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

If you want to change that you can change the define using build_opt.h feature:
https://github.com/stm32duino/wiki/wiki/Customize-build-options-using-build_opt.h

or you can simply change the default pins to use PA10/PA9 as explained in the Wiki:
https://github.com/stm32duino/wiki/wiki/API#hardwareserial

    Serial.setRx(PA10);
    Serial.setTx(PA9);
    Serial.begin(9600);

Note those pins are linked to USART1 not USART2 like PA2/PA3.