Epson FX-286 - Impact Printer, Руководство пользователя

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The graphics command requires more than one number to specify
how many columns to reserve because as many as 1920 columns on an
eight-inch line are possible in graphics printing. Since the FX-286
doesn’t use decimal numbers larger than 255, the graphics mode com-
mand uses two numbers for reserving columns.
To figure the number of columns reserved, multiply the second
number by
256
and add it to the first number. Since the command is
set up for two numbers, you must supply two even if you only need
one. When you need less than 256 columns, just make n1 the number
of columns you are reserving and make n2 a zero.
Pin Labels
Once you put the printer into graphics mode and reserve the num-
ber of columns you
want,
your next step is to tell the print head which
pins to fire in each column. There are
256
possible combinations of
eight pins, and you send only one number for each column. The num-
bering system that allows you to use a single number to specify which
of the 256 possible patterns you want is shown in Figure
6-1.
128
64
32
16
8
4
2
1
Figure 6-1. Pin labels
To fire any one pin, you send its number. To fire more than one pin
at the same time, add up the numbers of the pins and send the sum to
the printer. With these labels for the pins, you fire the top pin by
sending
128.
To fire the bottom graphics pin, you send 1. If you want
to fire only the top and bottom pins, you simply add 128 and 1, then
send 129.
By adding the appropriate label numbers together, you can fire any
combination of pins. Figure
6-2
shows three examples of how to calcu-
late the number that will fire a particular pattern of pins.
6-4