### Electric Crayon

The Electric Crayon is an external device that provides a colour video display. It can work with practically any computer as it connects via the printer port. It was primarily targeted at Model 1 and 3 users as the machines did not have a colour display nor high resolution graphics.

You may attach an emulated Electric Crayon to trs80gp by using `-p :ec` on the command line or bringing up the Printer → Connection... dialog box and choosing "Electric Crayon" from the dropdown. In either case a new instance of trs80gp will run acting as an Electric Crayon emulator. When launched this way the Electric Crayon emulator will go away when you quit the main trs80gp program.

Even with an Electric Crayon attached trs80gp still records the output to the printer in the normal window. This can be very handy to capture a drawing or debug a program using the Electric Crayon.

You can also just run a standalone Electric Crayon emulation via `trs80gp -mec` and hook it to another trs80gp emulator using the `-p` command line options to map TCP/IP connections to the printer port. The Printer section gives some more details on how to do that.

Although the owner had no direct control over the real Electric Crayon, trs80gp supports pasting text to its command processor. Thus even run standalone you can draw using the usual paste methods: Edit → Paste, the input macros or `-i` on the command line. For example:

           trs80gp -mec -i "A 10 4 HELLO WORLD\r"

Not many programs were written for the Electric Crayon. Here's quick overview of the available commands so you can write some yourself. You can get more detail from the January 1981 issue of 80 Microcomputer. However, don't miss out on the fun of playing with the commands and figuring it out yourself.

Command |  | Operation
--- | --- | ---
`A x y string` |  | Display text string.
`C n` |  | Select colour.
`ERS` |  | Erase display.
`H x y len` |  | Draw horizontal line.
`M n` |  | Change graphics mode.
`I` |  | Invert. (swap between the two palettes)
`LD*` |  | Load data or code in S record format.
`P n` |  | Set semigraphics value written when drawing.
`R x y string` |  | Display string in reversed colours.
`S x y` |  | Set pixel (or P pattern if in semigraphics)
`V x y len` |  | Draw vertical line.

        Graphics Modes:

        0	alphanumerics and semigraphics-4
        1	2 x 3 semigraphics-6
        2	 64 x  64 x 4 graphics
        3	128 x  64 x 2 graphics
        4	128 x  64 x 4 graphics
        5	128 x  96 x 2 graphics
        6	128 x  96 x 4 graphics
        7	128 x 192 x 2 graphics
        8	128 x 192 x 4 graphics
        9	256 x 192 x 2 graphics

The Electric Crayon's 6800 CPU is fullly emulated. There's a debugger and the usual trs80gp programming features.