char array as function parameter

I made a function that takes a char array as a parameter, and when I compiled it, it was fine. But when I tried to run the function to test it out, it gave me a error saying " In function 'void loop()': error: invalid conversion from 'char' to 'char*' "

here is the line of my function that accepts a char array: int hexPlusOne(char originalHexNum[2]){

and here is the code I was using to run the function: void loop(){ Serial.print(hexPlusOne('5','4'); }

Can anyone provide any help?

 Serial.print(hexPlusOne('5','4');

You can’t invent syntax to create an array like that.

char myArray [2] = {'5', '4'};
...
Serial.print(hexPlusOne(myArray);