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(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. | 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 | It responds on any port with A2 set low. | ||
== | {| class="wikitable" style="text-align: center;" | ||
|- | |||
! rowspan="2" style="width: 5em;" | | |||
! colspan="8" | Bit | |||
|- | |||
! style="width: 5em;" | 7 | |||
! style="width: 5em;" | 6 | |||
! style="width: 5em;" | 5 | |||
! style="width: 5em;" | 4 | |||
! style="width: 5em;" | 3 | |||
! style="width: 5em;" | 2 | |||
! style="width: 5em;" | 1 | |||
! style="width: 5em;" | 0 | |||
|- | |||
! style="height: 5em;" | Read | |||
| Paper start latch || 0 || 1 || 1 || 1 || 1 || 1 || Next pixel latch | |||
|- | |||
! style="height: 5em;" | Write | |||
| Stylus power || || || || || Motor Power || Motor speed || | |||
|} | |||
* Paper start latch: raised when the stylus reaches the start of the paper, or when stylus power is turned on. | |||
* | * Next pixel latch: raised when the stylus reaches the next pixel (approximately every 250 T-states when motor fast) | ||
* | |||
* Stylus power: 0=off, 1=on | |||
* Motor power: 0=run, 1=stop | |||
* Motor speed: 0=fast, 1=slow (no effect if motor stopped) | |||
Any I/O write to the printer also resets the latched signals. | |||
==BASIC commands== | ==BASIC commands== |