USART Receive multiple characters

[Indois]

Hello,

I am trying to recognize a number sent to USART:

If I send '123' over USART to MCU then MCU receives only '3' (the last character). Variable recv has uint8_t (unsigned integer) type. How could I receive the complete number ('123')?

I am using STM32L0 MCU and STM32CubeIDE environment.

Thank you.

[waclawek.jan]

> if (recv == '123')

> If I send '123' over USART to MCU then MCU receives only '3' (the last character).

From the C standard:

The value of an integer character constant containing more than one character (e.g.,

'ab'), or containing a character or escape sequence that does not map to a single-byte

execution character, is implementation-defined.

In other words, it depends on the compiler, how is '123' interpreted; however, the result is a single number, not any magical way to compare multiple possible values.

You may want to look up the strchr() standard library function.

JW

[Tesla DeLorean]

You'd need to accumulate a byte at a time into a buffer, and then parse when you have enough data to work with.

A single byte could hold the value 123, ie (recv == 123)

Or in ASCII it would be a string containing three decimal digits, ie "123"