Retarget scanf on STM32G070RBxx Cortex M0+

[AVerm.4]

(originally a reply to https://community.st.com/t5/stm32cubeide-mcus/retarget-printf-on-stm32g070rbxx-cortex-m0/td-p/720883)

Hi @Andrew Neil,

For the scanf do we need to make any other change?

My read function is-

int _read(int fd, char *ptr, int len){
  (void)fd;
  int i;
  for(i=0;i<len;i++){
    *ptr++ = uart_read();
  }
  return len;
}

In the terminal window it is not taking any keypress.

[Andrew Neil]

I've not tried it.

I guess you would still need to do the extern "C" and anything else specific to C++ ...

[AVerm.4]

@Andrew Neil 

This I'm trying on C. The cursor doesn't take input on keypress.

[Andrew Neil]

---

@AVerm.4 wrote:

the cursor doesn't take input on keypress.

---

What do you mean by that?

Do you mean the keypress doesn't appear on your terminal?

If you want that, it's called echo - it can be either local or remote:

• Local - performed purely in the terminal itself
• Remote - the echo is performed by your software.

Again, beware of the line buffering.

If you put a breakpoint in your _read function, is it hit ?

[AVerm.4]

Both the local and remote echo is working fine. now, i have to handle CR so that on pressing Enter key the code should return to main function.

Also it is hitting my read function correctly.!

[Pavel A. · Accepted solution]

setbuf(stdin, NULL);

[Andrew Neil]

---

@AVerm.4 wrote:

Both the local and remote echo is working fine.

---

So what did you mean by, "The cursor doesn't take input on keypress", then ?

[AVerm.4]

It was not visible on my terminal. So enabled it in settings.

[Andrew Neil]

Right - so it was an echo setting, then?

[AVerm.4]

Exactly !