Epson M X - 8 0 Manual De Usuario

(7) NUL ( N u l l )

The NUL code is regarded as the termination for tabulation setting sequence.

The lack of the NUL code would cause incorrect data printout.

Input of this code in the Text Mode causes the Printer’s operation mode to be

converted from Text to Normal-density Bit Image. Refer to paragraph 4.1,

section 4, for details.

Input of this code in the Text Mode causes the Printer to perform dual-density

bit image printing. Refer to paragraph 4.2, section 4, for details.

Most of the abovementioned control codes are normally used in the text mode.

C o n t r o l   c o d e s   a s s o c i a t e d   w i t h   t h e   B i t   I m a g e   m o d e   w i l l   b e   d i s c u s s e d   n e x t .

Each computer has its unique way of handling graphics.

For example, in the CBM computer there is a set of 64 special graphic characters

that can be used to draw and plot with. On the other hand, the APPLE II computer

has no graphic characters but a rich variety of graphic statements that allow you to

control any dot in a 280-by-193 screen matrix. As well as the latter “APPLE II,”

the MX-80 Type II has no character generated graphics but allow you to control

all the 8 needles freely and programmably by means of the so-called “Bit Image”.

To do that you have to switch the printer from the text mode to the bit image

mode by inputting an escape code. This bit image mode expands the ability of the

printer.

The printer enters bit image mode when ESC K or ESC L code is input, and utilizes

a raster scan technique that enables the printing of vertical columns of 8 dots across

a page during each pass of the print head. To receive bit image data, RAM (128

bytes) of an IC on the control circuit board is used exclusively. When the bit image

data received by the printer exceeds the RAM capacity, the printer will start

printing bit image data from the first-in data, so that the RAM may always be filled

up with data up to its capacity of 128 bytes.