two STM32 micro USART communication

[tomjianchun]

Posted on February 14, 2015 at 14:33

In my design, I am using two STM32 micro communicate with USART, the connection is as below, these two micro is in same board, and the communicate trace line length is around 1.5 inch.

STM32F030 (USART1_TX)  PA9------STM32F205(USART3_RX) PB11 STM32F030 (USART1_RX)  PA10-----STM32F205(USART3_TX) PB10 I am just directly connected as above, my question is : 1, Does I need to an outside pull up on both connections, if needed, the micro internal 40k ohm pull up is enough or not ? 2, Does I need to put two serial resistorS on these connections ? if no, is there any reliability issues ? Thanks.

[Tesla DeLorean]

Posted on February 14, 2015 at 14:47

Do they share a common supply? And will they be on at the same time?

[tomjianchun]

Posted on February 15, 2015 at 02:15

yes, both two STM32 micro is on the same +3.3V power supply rail, and they will be power on at the same time, and power off at the same time.

Thanks.

[Tesla DeLorean]

Posted on February 16, 2015 at 05:02

I'd just connect them directly together, just swapping the TX/RX.