Support Group Application Note No. 002, Issue 1 | 16th June 1992 |
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Using the Acorn JP101 Spark Jet Printer
Apart from being a remarkably quiet and fast home computer printer, the JP101 Spark Jet Printer has many special features which are simple to use and can improve the presentation of your printouts. Among these features are nine different national character sets, double width printing, double height printing, and horizontal and vertical tabulation functions.
The printer may be controlled from either a program or from the keyboard using VDU commands, or by typing control characters on the keyboard. For example, we can turn the printer on or off from the keyboard or from a BASIC program by typing VDU or VDU3. This may also be done from the keyboard by typing
When we wish the printer to perform a more complicated task, such as printing characters double width, or automatically tabulating data as it prints it out, then a sequence of commands must be sent to the printer to tell it how it must print any future characters the computer sends it. We wish to send these characters to the printer only and this may be done using VDU1 which sends the next character to the printer only.
In order that the printer should recognise characters sent to it by the computer as part of a command sequence rather than as characters to be printed they are preceded by an ESC character. This has the ASCII code number 27, so to send the ESC character to the printer only we use the command VDU1,27.
VDU commands may be strung together so we may send sequences of characters more easily. For example, to tell the printer that we wish it to print any further characters we send it as double width characters, we must send it the sequence ESC 3. To do this we use VDU1,27,1,51. 51 is the ASCII code for the character 3.
For more information about ASCII codes or VDU commands, see your computer's user guide. For more information about the operating commands of the JP101 printer, see the printer manual chapter 6.
Given below is a summary of the VDU commands you should use to obtain various effects on the JP101 printer. Note that before sending any VDU commands to the printer is possible, the printer must be enabled using a VDU2 (see example programs in 12) and 14) below).
1) Double Width Characters On
VDU1, 27, 1, 51 | This command turns double width printing on until it is turned off again. |
2) Double Width Characters Off
VDU1, 27, 1, 52 | This command turns off double width printing. |
3)Double Height Characters On VDU1, 27, 1, 39
This command turns on double height printing. It may also be used in conjunction with 1) to obtain double height, double width characters.
Support Group Application Note No. 002, Issue 1 | 2 |
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