USART1 without level-shifter?

asif · ‎2009-05-19

Posted on May 19, 2009 at 11:14

asif · ‎2011-05-17

Posted on May 17, 2011 at 13:12

Hello

I am just experimenting with an STM32F103 and would like to use the serial bootloader. As the USART1 pins are 5V tolerant so can I connect it directly to the COM1 on my PC?

Thanks

Asif

ivanov-i · ‎2011-05-17

Posted on May 17, 2011 at 13:12

No, you can not.

First, the signals on PC COM port are inverted.

Second, they swing between -10V and +10V.

Just put MAX3232 or some similar chip, which will do the job.

asif · ‎2011-05-17

Posted on May 17, 2011 at 13:12

Okay. Thank you for the information.