ZX Printer

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Revision as of 11:58, 10 June 2012 by Edward (talk | contribs) (The printer, its port, and BASIC commands to drive it)
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The ZX Printer prints on a roll of special metallised paper; it has a stylus which passes an electric current through the paper and blackens the surface.

It responds on any port with a2 low, such as 0xFD.

OUT effects

  • d7 - stylus power: 0=off, 1=on
  • d2 - motor power: 0=go, 1=stop
  • d1 - motor speed: 0=fast, 1=slow (no effect if motor stopped)

Any OUT to the printer also clears the latched IN signals (see below).

IN response

  • d7 - latched 1 when the stylus reaches the start of the paper
  • d6 - pulled 0 if ZX Printer connected
  • d0 - latched 1 each time the stylus reaches the next pixel (about every 250T when motor fast)

All other bits 1. Note that IN does not clear the latched signals.

BASIC commands

  • COPY (Z) will print the current screen (pixel data only; the state of attributes is ignored, so you might get some bits of your picture inverted).
  • LPRINT (Extend-C) acts like PRINT but sends output to the printer.
  • LLIST (Extend-V) acts like LIST.