How to have user input (Nucleo-F401RE)

Mbed OS
1

I am trying to make a system that takes a numeric user input in the console and then spins a motor that many times
(I want to have 2 inputs and 2 motors but I want to start smaller and build up, I also in the future want it to be able to read the inputs from a text file)
I have been looking at a lot of documentation that is out there relating to BufferedSerial but nothing I have tried seems to work.
Does anyone have any suggestions???

2

Hello,

BufferedSerial sometimes can only read a part of the whole string (It is not affected by size of the buffer but probably by a processor speed/load), so you must collect all the parts and then process them.

For code example click here 
#include "mbed.h"
#include <string>
#define MAXIMUM_BUFFER_SIZE 10
#define FORMAT "1-100"

DigitalOut          led(LED1);

static BufferedSerial serial_port(USBTX, USBRX);

int main(){

    printf("Example start\nPlease enter motor ID and number of steps of that motor.\n");
    printf("ID-Steps \nFormat: %s\n", FORMAT);
    char buf[MAXIMUM_BUFFER_SIZE];
    string myString;
    int counter = 0;

    while (1) {
        if (uint32_t num = serial_port.read(buf, sizeof(buf))) {
            // convert to string
            for (int i = 0; i < num; i++) { 
                // only string without  new line and carriage return
                if('\r' != buf[i] && '\n' != buf[i]){
                    myString += buf[i];
                    counter++;
                }
            } 
            // is complete
            if (counter >= sizeof(FORMAT)-1){
                int motorID = stoi(&myString[0]);
                int motorSteps = stoi(&myString[2]);
                // your motor magic here
                printf("Motor %d will run for %d steps\n", motorID, motorSteps);
                myString = "";
                counter = 0;
            }
            led = !led;
        }
    }
}

It has been tested with this setup:

  • MbedOS 6.7,
  • MbedStudio 1.3.1
  • Boards - Nucleo-F429ZI, F446RE, F303RE
  • Serial terminals - Termite, Hercules, Putty and also Serial Monitor of the MbedStudio.

BR, Jan

4

Hello, Thank you for the help so far, I ran the code to ensure it would work and the output is looking like this
do you know what this might be, is it related to the buffer size?

internetCodeOutput
internetCodeOutput715×54 8.77 KB

5

Hmm, I don’t know.
Just try to commented out the first printf, that string is not necessary it is only for info how to use the rest.

BR, Jan