Epson LX-80, Руководство по эксплуатации

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Thi s driv e r will also work on the TRS-80 Model III-with one
ch a n ge in line 10: change 32E837 to D3FB.
Solutions for 7-Bit Systems
Th e BASIC language on some computers can only send sev en bits
to t he printer at one time , even though the machine langua ge may
b e a bl e t o se nd eight . (The Apple II Plus is a case in point). On such
com pu ters , th e CHR$ function cannot send the entire r a n ge of
ASC II co d es (0-255) to the printer ; it can send only the low er half
(0 - 12 7 ) .
To fi nd o ut whether your system is an 8-bit system , c a p a b le of
ge n era t i n g a ll 2 56 ASCII codes , enter this simple test:
1 0 FOR X = 160 TO 254
20 L PRINT CHR$(X);
3 0 NJt ~ XT
X
If yo u get italic characters when you RUN this , you ar e u s in g an
8 - b it sys t e m .
If yo u h ave a 7-bit system , you need to understand what happ ens to
t h e co n t r o l cod e s you send. The LX-80 automatically int erprets
t h ese codes th e way y our s ystem s ends them-as the lower h a l f of
th e r a n ge. T here is something you may be able to do when y ou want
t o se n d th e upper half (128-255) : have your program conv er t all
codes o ut side of the active range to their equivalent in the upp er half
b y ad d i n g 128 to them .
Th e p r o bl e ms that are associated with 7-bit systems includ e :
• Limit at i o n s on width in graphics mode
• In ab ilit y to use the top pin for graphics mode
U se r - d e f i n e d ch a racters cannot be printed with the top eight pins
( th e sta nd a rd position for most characters). Also eight pin s ca nn ot
b e u se d in defining characters.
R e m e m be r th a t the be s t solution usually is to use an interfa ce that
ca n se nd e i g ht bits to the printer .