Printronix P9000 Series - Manual (Page 87)

5-7 Vertical Format Units
Start Load Code - 6C, 6D, or 6E Hex
6E Hex - The DVFU start load code of 6E (hex) with the PI line high initiates the DVFU memĆ
ory load routine using the current printer line spacing as the DVFU line spacing.
6C Hex - The DVFU start load code of 6C (hex) with the PI line high initiates the DVFU memĆ
ory load routine using 6 lpi as the line spacing regardless of the current printer line spacing.
6D Hex - The DVFU start load code of 6D (hex) with the PI line high initiates the DVFU
memory load routine using 8 lpi as the line spacing regardless of the current printer line spacĆ
ing.
Channel Assignment
Following the start load code, all data bytes received are interpreted as channel assignment
data until the end load code is received. During the channel assignment portion of the load
routine, the PI line can be high or low; if high, however, the channel data must not be the same
as start or end load code data. The last channel 12 loaded is assigned Bottom of Form (BOF). If
skip-over perforation is enabled, slewing will occur from BOF to TOF.
A maximum of 12 channels can be assigned to one physical line on the form (multiple channels
per line facilitate the use of a single DVFU load for multiple forms). Two eight-bit data bytes
(DVFU characters) are required per line. As shown in Table 5-4, the least significant 6 bits of
the first data byte are used to assign channels 1 through 6; the least significant 6 bits of the secĆ
ond data byte are used to assign channels 7 through 12. If a bit is set, the corresponding channel
is assigned.
Each line on the form requires two bytes. For lines not requiring a channel identification, the
two bytes should not contain channel assignments.
A maximum of 143 lines (286 DVFU bytes) can be assigned on the form. If more than 286 bytes
are received without an end load code, the end load code is forced" and the load routine is
terminated.
CH 1 TOF - The first channel, line 1 of the form, must be assigned channel 1, top-of-form, or
the entire load sequence is ignored and the memory reset. Consequently, when preparing to
load the DVFU memory, position the paper at the required top-of-form position in anticipaĆ
tion of sending the TOF channel assignment code as the first line loaded. After the memory is
loaded, a Form Feed code (FF, 0C hex) will move the paper tothe next channel 1 (top-of-
form).
CH 2 VT - Channel 2 is designated as the vertical tab channel. After the memory is loaded, a
VT code (0B hex) will move the paper to the next channel 2. If a VT code is received but chanĆ
nel 2 is not loaded, the paper will advance a single line at the current line spacing.
CH 12 BOF - The last channel 12 loaded is used as the bottom-of-form channel and has
significance when using the printer skip-over perforation feature. When skip-over perforaĆ
tion is enabled, paper will skip from BOF to TOF only if at the BOF position. If a channel
search moves paper past the BOF position but before the TOF position, no skip-over perforaĆ
tion will occur.