User's Manual

Control Code Definitions
—
Chapter
5
91
6820 Series 80-Column Printer User’s Manual
Select High-Speed Double Density Graphics Mode
This 8-pin graphics mode produces the same density as the Low-Speed
Double D ensity mode, however, the speed is doubled. Calculating the pa-
rameters, n1 and n2 , is d escribed on page 89.
Format
Decimal Hex ASCII
27 89 n1 n2 1B 59 n1 n2 ESC “Y” n1 n2
The resolution is still 120 dots per inch. Each 8-inch line can accommo-
date 960 columns of graphic dots. A graphic string that exceeds the length
oftheprintlineisdiscarded.Takecarethatadjacentdotsinagivendot
row are not printed.
Select Low-Speed Quadruple Density Graphics Mode
With this 8-pin graphics mode, the number of dots per inch has gone up
to 4x what it was in single density. Calculating the parameters, n1 and n2,
is described on page 89.
Format
Decimal Hex ASCII
27 90 n1 n2 1B 5A n1 n2 ESC “Z” n1 n2
The resolution is now 240 dots per inch. Each 8-inch line can accommo-
date 1920 columns of graphic dots. A graphic string that exceeds the
length of the print line is discarded. Take care that adjacent dots in a given
dot row are not printed.
Nine-Pin Graphics Modes
These 9-pin graphics functions also require two parameters, n1 and n2.
However, they are calculated slightly different than in the 8-pin graphics
modes. Since each d ot column to print must be represented by two data
bytes, the total length of the graphic string (following the Select ... Graphics
Mode command) needs to first be divided by two. These parameters are
calculated as follows (assuming a temporary variable n):
n = total number of dots needed, divided by 2
n2 = integer of (n divided by 256)
n1 =remainderofthen2calculation
First, divide n (the total number of dots needed for the graphics string) b y
2, then divide the result by 256. Then n2 is the quotient (the whole num-
ber) and n1 is the remainder. If you require less than 256 dots (columns),
then n1 indicates the number of dots and n2 is set to zero.