How to send a character to uart by its code?

Question

bash

How to use bash to send characters to uart by their codes?
Are there any differences between character representations in uart/linux/bash/stm32 ?
what determines how many bits / bytes the function of reading one character by uart will receive?

Answer 1

How to use bash to send characters to uart by their codes?

export hexcode=41 #'A'
printf "\x$hexcode" > /dev/ttyS0

Есть ли различия между представлениями символа в uart/linux/bash/stm32 ?

man ascii , man charsets

what determines how many bits / bytes the function of reading one character by uart will receive?

The number of bits in a character depends on the UART settings, see man stty , parameter cs. Normally the UART read APIs operate on bytes.