Printronix P9000 Series, User'S Reference Manual

Page: 83 / 334

5-3 Vertical Format Units
Channel 1 - The top-of-form code, reserved as the first line on the form or the first line
printed (top-of-form position). 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) will
move the paper tothe next channel 1 (top-of-form).
Channels 2 through 11, 13 and 14 - Used as general channel codes (line identification codes)
or filler channels. Each line on the form must be identified by a channel code. When the operatĆ
ing program sends the channel code, the paper advances to the line identified by the channel
code. Lines not used by the operating program must be identified by filler channels (unused
channel codes).
Channel 12 - Reserved as the Vertical Tab channel. The Vertical Tab code (VT, 0B hex) prints
any data in the print buffer and rapidly slews the paper to the next line identified by the channel
12 code. If channel 12 is not loaded in the EVFU memory, a single line feed will be executed
when a VT code is sent.
Channel 15 and 16 - Used as general channel codes or filler channels only when the VFU is
accessed by the PI line. In an EVFU form that does not use the PI line, the codes for Channels
15 and 16 function as the Start Load and End Load codes.
End Load - 1F or 6F Hex
The end load code terminates the memory load program. The end load code is 1F hex when the
PI line is disabled (low) or 6F hex when the PI line is high. Channel codes in excess of 192 chanĆ
nels received prior to the end load code are discarded.
Using the EVFU
Once the EVFU program has been enabled and loaded, the VFU LOADED indicator on the
control panel lights. Sending the appropriate channel code to the printer will cause 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.
For a data byte to be recognized as an EVFU instruction, the following criteria must be met:
1. PI line must be enabled and set high; and
2. Data bit 5 must be 0 (not set).
OR:
1. PI line must be disabled or low; and
2. Data bit 5 must be 1 (set).
Given these conditions, the lower four bits of a byte will specify the EVFU channel number.
Table 5-1 lists the EVFU channels and their equivalent data bytes with the PI line enabled;
Table 5-2 lists the EVFU channel and their equivalent data bytes with the PI line disabled.