Download Character Codes - Epson FX-80 Operation Manual

Download Character Control Codes
Download characters (user-defined character set)
Scientific symbols, special characters, etc., can be defined by the user and output on
the printer. Characters printed in this manner are called Download characters.
Download characters can be defined as part of the Character Code Table. A
maximum of 256 download characters can be defined and stored in the RAM of the
printer.
The memory of the printer is a RAM, the contents of which are lost when the
power of the printer is turned OFF. Therefore, when power is applied to the
printer, its RAM memory contains no data. In contrast, the printer is also provided
with a ROM. The nature of a ROM (Read Only Memory) is that the data in the
ROM is retained regardless of whether power is being supplied or not. The ROM
of the printer. stores the controls for the printer operation, various functions, ROM
programs, etc.
Normally, the printer uses the internal character set stored in the ROM. The
internal character set includes all of the characters on the Character Code Table
(including international character sets). To use Download characters, it is
necessary to change from print operation using the internal character set to one
using a different character set. In other words, it is necessary to change from the
internal character set in the ROM to the Download character set in the RAM. The
characters in both the Download and the internal character sets are referenced by
addresses (0)0 to (255)0·
Let's take an example of actually defining and using a Download character.
First, the Download character must be written to the RAM. Since Download
characters are written to the RAM, when power is applied to the printer, there are
no characters in this set. To write a Download character to the RAM, the location
where the character is to be written must first be specified and then the character
pattern data sent to the RAM.
For this example, let's specify the location for writing the Download character as
(65)0' the location in the internal character set for character "A".
When the location is specified and the character pattern data is sent, the definition
of the Download character is complete. Defining and sending the character pattern
data is explained later. However, merely defining the Download character in
location (65)0 is not enough to print it. The RAM must be specified as the place
where the character pattern data is stored. This is done by sending the ESC % 1 0
code to the printer. This selection of the RAM may be performed either before or
after the Download character is defined. Then, when LPRINT CHR$(65) is sent to
the printer, the Download character which you have defined will be printed.
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