Epson LX-80, Operating Manual

Page: 165 / 193

It is best to fi r s t t e st to see if the printer is ready by u s ing a l i n e such
as :
This puts t h e pr o gram into a continuou s loop until the pr i nter i s
ready to receive d a t a. I f data is s ent whil e the printer i s bu sy, it will
be lost .
To show how s imil a r th ese c o mm a nd s c a n b e fr o m sys t e m to syst e m ,
here is the sa me concept implemented on the Appl e® II P lus with
the EPSON 8 1 31 or 8 13 2 int e rf a c e c a rd s :
100 IF P EEK(49601»127 THEN 100
200 POKE 49 2 96 , N
The status of t he print e r i s s t ore d in l o c a tion 49601 a nd th e outgoin g
values are sen t t o 4 92 9 6.
Special pri n t er drivers
An even better ( but mor e di f f ic ult ) way to o ve rc o m e th ese problem s
is to modify the print e r dri ver so th a t th e c od es a r e p assed correctl y
to the printer w ithout a n y P E EK s or POKE s . I f y ou d o n ot want t o
write such a d r ive r y our se lf , y our computer d ea l er m ay b e able t o
help you , or yo u m ay find o n e in a co mput e r ma g azin e, or from a
computer user gr o up.
The following p rint er dr ive r , f o r i n s t a nc e, w as w ritt e n f o r t he TRS-
80 Model I by Bob Booth e a nd r e p r int e d with the kind p ermission
of
80 Micro
(Way n e Gr ee n Publi s her s). The progr a m P OKEs a
machine-language print er dr ive r progr a m (s tor e d in lin e 10) int o
memory , then t e ll s th e sys t e m wh e r e its n e w driv e r i s locat ed. Onc e
you RUN the pr og r a m , a ll co d es se nt b y an y BASI C pr ogram ar e
sent directly to t h e print e r-in c luding O s, lO s, a nd 12s.
10 DATA 2 1E837CB7E20FC211100397E32E837C 9
20 READ B $ : A=16571
30 FOR P= l TO I . F : N (R$) STEP 2
40 B=ASC( MID$(B$ , P, 1» - 48
50 IF B>9 THEN B = B - 7
60 T=ASC( MID$(B$ , P + 1,1» - 48
70 IF 1'>9 T H EN 1'=1' - 7
80 POKE A, B*16 + l'
90 A=A+1
100 NEXT P
110 POKE 16422,187
120 POKE 16423,64