Are the USART*_TX pins configured as push-pull outputs when in system memory mode from the beginning or only after selection of the USART interface (0x7F received)?

[ChristophR]

Hi,

AN2606 (STM32 microcontroller system memory boot mode) states e.g. for the STM32F301, that in system memory boot mode both USART_TX pins (USART1_TX & USART2_TX) are used as outputs.

Is the TX pins really configured as outputs as soon as the system memory mode is entered, or are the pins only configured as outputs as soon as the UART frame 0x7F for bootloader selection is received on the USART_RX pin?

Thanks!

Best regards,

Christoph

[waclawek.jan]

Tx will be turned to output only after the 0x7F received. There may be some pull-ups switched on before that.

JW