I'm using Adafruit 0.54" Quad Alphanumeric FeatherWing Displays with I2C interface and the libraries:
#include <Adafruit_GFX.h>
#include "Adafruit_LEDBackpack.h"
I am new to Arduino and have little experience of C/C++
In the example sketches Adafruit give ASCII and Raw functions for writing to the display 1 digit at a time e.g.
alpha4.writeDigitRaw(digitNum, 0x3FFF); // Raw bitmap of the LED segments
alpha4.writeDigitAscii(digitNum, '8'); // Ascii character to a display digit
I am using the ASCII version.
I don't know which GFX commands (if any) can be used with this display, but I had to put 4 displays together for 16 digits which means using 4x I2C addresses each with 4 digits and a different object for each 4-digit display (alpha1, alpha2, alpha3, alpha4)
Maybe a different display would be easier, but I chose this one as the 14 segment display is like the HP-41C calculator!
So a dtoa or dtostr funtion would fit into the software I have written, but if there is a way to print double numbers that would be best!
Is there documentation giving a list of commands and syntax for each of the libraries?