User manual EPSON MX-70

[. . . ] User's Manual for MX-70 Printer by David A. Lien C O M P U S O F T ® PUBLISHING A Division of CompuSoft, Inc. Box 19669 l San Diego, California 92119 U. S. A. This Book was prepared especially for Epson America, Inc. All rights, domestic and international are reserved by CompuSoft ®, Inc. [. . . ] Here is how the program works: Line 10 sets line spacing to 1 DOT (1) Line 20 PRINTS something we want to underline Line 30 PRINTS 9 underlines. (Computers that support STRING$ could use it here. ) The ; suppresses the LF. 38 An Introduction to Dot Matrix Printing Line 40 returns line spacing to the normal 12 DOTS Line 50 PRINTS more text to show that all is normal and that's plenty to think about in this chapter. Code Summary CHR$ (27) "A" CHR$ (##) - SETS LINE SPACING TO ## DOTS (O <= ## <= 85) CHR$ (27) "2" - RETURNS LINE SPACING TO 12 DOTS CHR$ (10) - LINE FEED CHR$ (13) - CARRIAGE RETURN CHR$ (95) - UNDERLINE CHARACTER 39 Graphtrax II Chapter 5 Graphtrax II Caution - Entering High Resolution Space To create graphics on the MX-70, we must enter a completely new mode: the GRAPHICS MODE. In this mode, pre-defined characters do not exist - only dots. We create our own characters or images by arranging the dots however we wish. In the GRAPHICS mode we have complete control over which pins fire, and when. It sounds like a lot of fun, and is, but there are an awful lot of dots in just one line, let alone an entire page. There are 80 "regular" characters in a normal line (row). Each character is 6 dots wide (5 dots plus 1 blank column). Fortunately, we don't have to fill all 480 columns on every line. In fact, the first thing we do when entering graphics mode is tell the printer how many columns of dots we will send it, a row at a time. Warp 3 The graphics mode is entered by sending the printer a cluster or sequence of 3 codes: FORMAT: EXAMPLE: <ESC> "K" ----------CHR$ (27) "K" N1 ---------CHR$ (15) N2 ------CHR$ (0) CHR$ (27) is of course the Escape code, and Escape "K" means KICK into graphics mode. CHR$ (15) says: "reserve 15 columns for graphics. " N1 can range from 0 to 255 (O-127 for 7 bit computers) CHR$ (0) If N2 is 0, it means "Ignore me, N1 specifies the number of columns to expect. " If N2 is 1, the number of columns will equal N1 + 256. If this sum of N1 and N2 exceeds 480, only 480 columns will be reserved. 41 Chapter 5 The Saki flowed like melting snow from Mt. Fuji when they contrived that wild scheme. Suppose we want to shoot 100 columns of graphics to the printer, on one row. What numbers would we use for N1 and N2?CHR$ (l00) CHR$ (0) Ok, so we got lucky. Let's try: CHR$ (44) CHR$ (1) Since N2 = CHR$ (1), 256 is added to N1. Enter these lines, but don't RUN: (Apple) 10 PRINT CHR$ (27) "K" CHR$ (50) CHR$ (0); TRS-80 Model I use: 10 LPRINT CHR$ (27) "K" CHR$ (50) CHR$ (2) ; 9 PR #1 for 100 columns The Model I can't send CHR$ (0) reliably, and ANY EVEN number is interpreted as a zero in the ESC K sequence here in Graphtrax II. How many columns is line 10 reserving, 50 or 306?Don't RUN yet. Firing the Pins There are 9 pins in the MX-70 print head. In graphics mode, we have control of the top 8 (the middle 7 for 7 bit computers). 42 Graphtrax II We'll label these top 8 pins as follows: 128 - 0 64 - o 32 - o 16 - o 8 O TOP 4-o 2-o l-o o BOTTOM (Ninth pin not used) From now on we will refer to the second pin (pin 1 above) as the "bottom" pin when using graphics. Well, the numbers shown are the actual ASCII numbers that fire the respective pins. [. . . ] The result is the estimated print head life in days. (Then count the legs and divide by four . . ) If and when the print head needs replacement, make sure it is cool to the touch. It may operate very hot under heavy use. [. . . ]