The program included a tone function which is also an Arduino built-in function so the compiler threw warnings it didn't know which to use. Changed the local function to fhtone to disambiguate as to which function to use and changed parameters to floats per the function spec.
A hardcoded value of 0x808080 was in the code for a mid-level grey. This is an RGB888 value, but the ST77XX library uses RGB565 values. A mid-grey in RGB565 is 0x8410. A local define was done to define this as STS77XX_GREY and the new value placed in the calls previously using 0x808080. This solves a compiler integer overflow warning preventing CI from completing.
