Epson LX-86TM Spezifikationen PDF herunterladen (Seite 53)

REV.-A

@ The CPU detects the

STRB

signal from the gate array (Reads MMIO and

XXOI

H). When the gate

array detects the trailing edge of the

STRB

signal, it automatically sets the BUSY signal HIGH and

latches the transferred data.

@ The CPU fetches the data latched by the gate array (reads MMIO and

XXOOH),

and stores the data

in the input buffer. The CPU analyzes each byte of data to determine whether it is a control code

or print data, then returns the ACK signal to the interface.

@ Steps@ and@ are repeated until the input data buffer becomes

full.

When the buffer becomes full,

the BUSY signal is set HIGH.

@ Either during steps@ and@ or after the input data buffer becomes fuil, the CPU analyzes each byte

of data. If the data is not a printing command (CR), the CPU sets the printing mode and parameters

and transfers the data to the line buffer. The line buffer is shown in Figure 2-16.

—

----

Character

Attribute

Character

code

2 code

-- -

—lb’’e+lb’ta-t-lb’te

3bytes (every 1 data)

Fig. 2-16. Line Buffer

The line buffer temporarily stores the data for one line using the format shown in Figure 2-16, and

also contains the command flags (1 6 bits), for attributes 1 and 2, for each character. The command

flags indicate what kind of command or mode is specified for the character. According to the

command flags, any of the EPSON

ESC/P commands,

NLQ,

underline, emphasized character, and

font selection, is specified for the character.

When either the CPU detects a printing command (CR) or the line buffer becomes full, the printing

process (interrupt routine) is started.

The CPU transfers the character codes from the line buffer to the CG (Character Generator), and

transfers image data to the

copy area. The

copy area refers to the attribute flags in the line

buffer and expands the image data. The expanded data is then transferred to the image buffer.

The CPU writes the (vertical) dot patterns in the image buffer to port HD of the gate array (writes

MMIO, XX04H, and XX05H). At the same time, the CPU references the contents of the line buffer,

and outputs the FIRE signal (which corresponds to the dot patterns expanded in the image buffer)

to the gate array.

When the

NLQ

mode is selected, note the following difference from the Draft mode:

● During command analysis in step

@, if the data is determined to bean

NLQ

character, the steps after

step

@ are repeated two times for every one pass (NLQ requires two-pass printing).

When the download mode is selected, the following point is different from the draft mode:

● When referencing the CG in step

@, the CPU accesses the down load buffer but not the CG.

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