Sharp FO-3150 Service Manual page 83

(6) IC8 ( PD65944) Hardware description
1) ASIC Functional Description
• Serial data reception from FaxEngine
• FaxEngine external bus connection
• Print data smoothing
• Resolution change and image scaling (50% to 200%)
Horizontal scanning 203.2dpi -> 406.4dpi
Vertical scanning 97.79dpi (Standard)/195.58dpi (Fine)/391.16dpi (SuperFine) -> 391.16dpi
• Centering in horizontal scanning direction
• Buffer memory, page buffer control (SDRAM) and memory access control
• Compatible with multiple copying (repeat printing)
• Laser control, video signal output control
• Polygon motor/main charge drive waveform generation
• Pickup solenoid and heater lamp driven hardware protection
• Serial interface between microcomputer for engine control and PD780032A (PrinterEngine)
2) Print Data Conversion Process
Serial input
Serial data
buffer
Standard
203.2 x 97.79 dpi
Input resolution
Fine 203.2 x 195.58 dpi
Super Fine 203.2 x 391.16 dpi
1728 dot/line
3) ASIC Constitution
Smoothing
Vertical scan
resolution change
Fig. 6 Print Data Conversion Process
Fax Engine
Serial Data I/F FAX Engine Bus I/F
Serial data
Interrupt
reception
Controller
circuit
Serial input
buffer
1.5 MB
Smoothing
process
circuit
Intermediate
buffer
512 KB
Output control
for page conversion
Scale
completion signal
conversion
circuit
Page
buffer
6 MB
Video
output
Interface
Fig. 7 ASIC Constitution
Enlarge/reduce
Intermediate
Centering in horizontal
buffer
scan direction
406.4 x 391.16 dpi
406.4 x 391.16 dpi
406.4 x 391.16 dpi
3456 dot/line
CLK System Clock
32.256MHz 20.95261MHz
Fax Engine
Bus Interface
32.256
MHz
Local Bus-A
Memory SDRAM
Arbitrator Controller
All data
conversion
controller
(page control)
Interrupt
main charger
Local Bus-B
Controller
Hardware
Printer Engine
protection
Bus Interface
timer
Printer Engine
Bus I/F
Microcomputer
for engine control
(PrinterEngine)
Laser Printer Unit
5 – 10
FO-3150U/C
Page buffer
406.4 x 391.16 dpi
406.4 x 391.16 dpi
Print resolution
406.4 x 391.16 dpi
3456 dot/line
ASIC
Memory
Bus
x16 SDRAM
64Mbit
Polygon
control
Video data