Printronix LQH-HWTM Using the EVFU

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Appendix C Paper Motion Using the EVFU

The Start Load code clears and initializes the EVFU memory for channel

assignment storage. Refer to Table 25 or Table 26 for the appropriate start

load code.

The EVFU memory has the capacity for 92-line forms. The first line

identification code (channel code) in the EVFU load data defines the first li ne

on the form; the second line identification code defines the second line on the

form, etc. Each line must have a line identification code.

A single channel code is used repeatedly throughout a form to reserve blank

lines between defined channel codes and to maintain the correct forms

length. These “filler” channels can be any channel number except channel

code 1 (which is reserved for the top-of-form) and channel code 1 2 (which is

reserved as the vertical tab channel). In the EVFU example which begins on

page 289, filler channels are represented by a hex 11 code. Calls are rarely

made to filler channels because they do not specify a unique print position on

the form.

Channel 1 — The top-of-form code, reserved as the first line on the form. The

operating program sends the channel 1 code to advance to the top of the next

form. After the memory is loaded, a Form Feed code (FF, 0C hex) moves the

paper to the next channel 1 (top-of-form).

Channels 2 through 11, 13 and 14 — Used as general channel codes (also

referred to as line identification codes) or as filler channels. Each line on the

form must be identified by a channel code. When the operating program

sends the channel code, the paper advances to the line identified by the

channel code.

Channel 12 — Reserved as the vertical tab channel. The vertical tab code

(VT, 0B hex) rapidly advances the print position to the next line identified by

the channel 12 code. If channel 12 is not loaded in the EVFU memory, a

single line feed is executed when a VT code is sent.

The end load code terminates the channel storage and saves the EVFU in

memory. Refer to Table 25 or Table 26 for the appropriate end load code.

Channel codes in excess of 192 channels received prior to the end load c ode

cause an EXECUTE EVFU load error.

Using the EVFU

Sending the appropriate EVFU channel code to the printer causes any data in

the buffer to print and slew the paper to the next line on the form having the

specified channel number assigned in EVFU memory.

To recognize a data byte as an EVFU instruction, one of the following sets of

criteria must be met:

1. The PI line must be enabled and set high;

2. Bits 7 and 6 can be set to 1 or 0; and