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6 years, 6 months ago.

I don't understand how to use the function Serial.write()

I try to write a program of serial but it can't be compiled because of a error(Error: No instance of overloaded function "mbed::Serial::write" matches the argument list in "main.cpp", Line: 13, Col: 13). I don't understand how to use the function Serial.write() and I can't find any example.

This is my program:

  1. include "mbed.h"

Serial sv(PA_9, PA_10, 115200);

int main() {

unsigned char i = 0; unsigned char tab[5] = {0xFF,0x55,0xAA,0x33,0x23};

while(1) { i = (i + 1)%5; while(sv.writeable()==0); sv.write(tab[i],8); wait_us(3); } }

Thank you for your help!

1 Answer

Sarah Marsh
6 years, 6 months ago.

https://os.mbed.com/docs/v5.6/reference/serial.html

So, the function signature of write is write(const uint8_t *buffer, int length).

Here, with tab[i], you are passing in a single character, not a pointer to a character, as the function requires. In C++, an array of characters can be cast to char*, as the pointer will contain the address of the first element in the array of characters.

http://www.cplusplus.com/doc/tutorial/pointers/ Look for the section "pointers and arrays" to understand more about the above.

So, if you wanted to write the whole tab buffer, the syntax would be: sv.write(tab,sizeof(tab));

If you want to write a single characher you can use putc: sv.putc(tab[i])

Accepted Answer