Epson MX-70 Manual Do Utilizador
Advanced Graphics
Chapter 6
Advanced Graphics
Firing Pins at Seven Paces
The MX-70 allows any computer to control the firing of its 8 active pins by
simply sending ASCII code numbers between O-255. Conversely, these 256
code numbers are sufficient to control all 8 pins. Multi-line graphics programs
will therefore usually be done with a top-of-line to top-of-line spacing of 8 dots
(8/72”).
code numbers are sufficient to control all 8 pins. Multi-line graphics programs
will therefore usually be done with a top-of-line to top-of-line spacing of 8 dots
(8/72”).
As already repeated, many computers, or their printer interface boards, will not
control or pass code numbers greater than 127. These computers can control
control or pass code numbers greater than 127. These computers can control
only 7 of the 8 active pins in graphics mode. With that common computer
deficiency in mind, the examples in the remaining chapters are limited to 7 dots
per line.
deficiency in mind, the examples in the remaining chapters are limited to 7 dots
per line.
The limitation is not a crippling one. We just have to adjust for it. (The same
field of corn can be harvested by a 2-row corn picker as by a 4-row - it just
takes a little longer.)
field of corn can be harvested by a 2-row corn picker as by a 4-row - it just
takes a little longer.)
Users with ‘superior’ computers can follow right along at our 7 dot clip,
knowing that their computers can drive all 8 pins if desired, but not until we’ve
all finished the course.
knowing that their computers can drive all 8 pins if desired, but not until we’ve
all finished the course.
Housekeeping
Let’s develop a fairly complex graphics picture a step at a time. Everybody
start by typing in these lines:
start by typing in these lines:
9 PR
# l
(Apple)
10 PRINT CHR$ (27) "A" CHR$(7)
20 N=50
30
PRINT CHR$
(27)
"K" CHR$ (N) CHR$ (0);
TRS-80 Model I:
30 LPRINT CHR$ (27) "K" CHR$ (N) CHR$ (2);
but don’t RUN yet.
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