Craden Peripherals DP8 Low Density Graphics Commands, High Density Graphics Commands, DC3

ESC~C clears all data out of the buffer and switches the interface to Mode C.

3.10.4 Low Density Graphics Commands

These commands emulate low-density graphics printed by a 9-dot printhead. New applications should use the high-density graphics commands intended for a 24-dot printhead.

Low-density graphics may be printed at 60, 120 or 240 dots/inch (dpi) horizontally by 72 dpi vertically. ESC K sets 60 dpi, ESC L or ESC Y set 120 dpi and ESC Z sets 240 dpi. ESC Y prints at full speed but adjacent horizontal dots are prohibited. ESC L prints slower without this restriction. Each command is immediately followed by m and n, a 2 byte data count indicating that the number of following graphic data bytes is m + 256 X n. The maximum data count is 336 for ESC K, 672 for ESC L or ESC Y and 1344 for ESC Z. The high order bit of each graphics data byte is the highest and the low order bit is the lowest of 8 vertical dots printed in a single dot column. Each bit must be set to a 1 for the corresponding dot to be printed.

Low-density graphics may also be printed in C mode only at 60 or 120 dots/inch (dpi) horizontally by 72 or 144 dpi vertically. ESC A must precede each line of 60 dpi data with a maximum of 336 data bytes. ESC B must precede each line of 120 dpi data with a maximum of 672 bytes. Each line of data must be terminated by a feed command, usually a VT e. Each data byte is of the form 1ABCDEF where A is the lowest and F is the highest of 6 vertical dots printed in a single dot column. Each bit must be set to a 1 for the corresponding dot to be printed.

3.10.5 High Density Graphics Commands

High density 24 dot graphics are selected by ESC [ g m n P where m + 256 X n is the following graphics data byte count plus one and P selects graphics densities as follows:

P value: 0	1	2	8	9	10 or 11	12
Density: 60x72	120x72	120x72	60x180	120x180	180x180	360x180

P= 0, 1 and 2 are equivalent to low density ESC K, L and Y commands. P=10 prints at high speed but adjacent horizontal dots are prohibited. P=11 prints slower without this restriction. In the 180 dpi vertical modes, each group of 3 following graphics data bytes will be printed as one 24 dot vertical stroke where the first byte’s high order bit is the highest and the third byte’s low order bit is the lowest of the 24 vertical dots printed.

3.10.6 Display Commands

These C mode commands may be used in I mode by preceding them with an ESC.

BEL	immediately displays the following 16 characters on the upper line of the
	alphanumeric display. The characters must not be control characters and there
	must be exactly 16 displayable characters
FS	loads the lower display line just like BEL loads the upper line.
DC3	or ETB operate identically to a BEL command but all previously received print and
	document movement commands are executed before the upper line of the display
	is loaded.
GS	loads the lower display line just like DC3 loads the upper line.

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