Commodore Plus 4 - Page 386

374 Using Peripheral Devices
34 = toggle quote mode
145 = switch to upper case/graphics
146 = turn off reverse field
The MPS-801 is always operating in standard width character mode, double
width character mode, or dot mode, the default is standard width character
mode. In double width character mode, data bytes sent to the printer are inter
preted as characters to be printed at twice their normal width. In dot mode, data
bytes are interpreted as vertical dot patterns to be printed one column at a time.
These modes are switched with the CHR$ codes 8, 14, and 15. Each remains in
effect until another mode switch character is received (even after the file is closed
and program ends) or the printer is turned off.
The Character Modes In both standard and double width character mode, two
character sets are available. These are upper case/ graphics and upper/ lower case.
Choose which of these sets will be the default set by choosing a secondary address
of 0 (or omitting the secondary address) or 7 when opening the printer file.
Regardless of which choice is made, the CHR$ codes 17 (cursor down) and 145
(cursor up) can be used to switch between the sets on a given line. When a carriage
return is received, the character set is reset to the default (as chosen with the
secondary address).
In addition, the reversed image of each character is available. The CHR$ codes
18 (reverse on) and 146 (reverse off) can be used to switch between reversed and
normal characters on a given line. When a carriage return is received, reverse is
automatically turned off.
In either character mode, the spacing between lines is greater than the height of
a character (to enhance readability). This results in six lines per inch.
The print head can be positioned to any character position required by using
the CHR$(16) command. The two characters following the CHR$(16) are inter
preted as CHR$ codes for two-decimal digits specifying the desired character
position of the print head. For example,
PRINT#4,CHR$(16)//10THIS IS A TEST."
prints the sentence starting in position 10 (counting from 0). This position is the
same whether in standard or double width mode.
Quote mode for the printer is similar to quote mode for the screen. That is,
after an odd number of CHR$(34) codes on a given line, control codes are printed
as reversed characters rather than interpreted as commands until another
CHR$(34) or a carriage return is received.