Unofficial Name: penBGColor
Memory Address: A036h
Length: 2 bytes
Stores the current RGB background color, used for small-font text display.
Colors are represented as a 5-6-5 value (5 bits of red, 6 bits of green, 5 bits of blue.) For example, 0000001111100000b, or 03E0h, would be dark green. 1111100000011111b, or 0F81Fh, would be bright magenta.
When drawing text to the graph buffer (write_on_graph flag set), it is assumed that the background color is either white (FFFFh) or medium gray (C618h).