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Print Engine Interface
MOTOROLA
MC68322 USER’S MANUAL
10-3
10.1.2 PVC Control Register
The PVC control register (PVCCR) contains bits that control the polarity of all MC68322
inputs and outputs used by the PVC. The PVCCR should be written after an MC68322 reset
and before a print operation begins.
Figure 10-2. PVC Control Register
While the PVC is active, the polarity of input signals should not be altered. The PVC
responds to a polarity change if it occurs while the PVC is waiting for a transition, but this
should be avoided. The PVCCR also contains the video clock source control bits, the PLL
video clock divisor control, and the SmartToner control bits.
SDN—SmartToner Density
This field selects one of four halftone patterns, where 00
2 =
1/
2 density, 012 =
1/
4 density,
10
2 =
1/
6 density, and 112 =
1/
8 density. This will affect the amount of toner used and the
quality of the printed page when the SmartToner feature is enabled.
SLC and SRC—SmartToner Left and Right Edge Control
These fields are used to select which dot the halftone pattern is applied to on the left and
right edges of a character. If the halftone pattern starts and ends on the first dot, then the
character will appear more jagged than if it starts and ends on the second or third dot. For
example, if the halftone pattern starts and ends on the second dot, then the character will
have a one dot wide border on the left and right sides, with the halftone pattern applied in
between.
PLE—PLL Edge
This bit is set to clock on both edges and clear to clock on rising edge only.
PLD—PLL Divisor
This field controls the PLL video clock prescaler. A PLD value of 00
2, 012, 102, or 112 causes
the VCLK input to prescale by one, two, three, or four before clocking the 8
× PLL.
Table 10-1. SLC and SRC Encodings
ENCODING
HALFTONE PATTERN
00
1st Dot
01
2nd Dot
10
3rd Dot
11
Not Used
= RESERVED
15
14
13
12
11
10
9
8
7
65432
1
0
15
14
13
12
11
10
9
8
7
65432
1
0
PRT
00FFF400
00FFF402
VCS
VCP
LSP
FSP
PRP
BDP
VDP
PLD
PLE
SRC
SLC
SDN
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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