BenQ PB8220 - XGA DLP Projector, Service Manual

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Pixelworks scaler (PW166) with x86 CPU and OSD and SDRAM are used for system control. It
control hole system operation and with crucial role of this system. The CPU controls the whole
system is embedded inside the Image Processor, there is also a Real Time Operating System that
incorporates with the CPU as hardware layer interface. The EEPROM stores the system
information such like brightness, contrast etc., which ensure the system operates under the most
user-friendly circumstance. The Flash memory stored the Software Program that controls the
system, and the CPU will read the Flash as its execution command.
Image Processor (PW166)
The most important IC is the image Processor, which here below list its main function
- Supporting input digital data stream up to UVGA and output digital data up to SXGA
- Two input port, which are Graphic port (VGA format) and Video port (video decoder format).
- Frame rate conversion, the output frame rate is independent from the input frame rate and the
most important feature of the Image Processor is memory inside, there is no need of external
memory for frame rate conversion.
- Up and Down scaling of different input resolution, ensure the same output image size.
- Providing Bitmap OSD picture, which if more fancy than normal OSD chip.
- On chip Microprocessor:
The Image Processor is a highly integrated circuit, it include MCU,
Scaler, Memory, OSD. This will increase the stability of the system.
There is some control signals list below
DCLK –
pixel clock output to DMD driver BD, provided as a reference clock for DMD driver
DVS
– Vertical synchronization signal output to DMD BD, provided as Vertical reference signal for DMD driver.
DHS
– Horizontal synchronization signal output to DMD BD, provided as Horizontal reference signal for DMD
driver.
DENG, DENR, DENB –
Data enable signal output to DMD BD, provided as a valid data indicator signal for DMD
driver. The DX760 only use DENG as Data Enable.
VCLK –
V-port pixel clock.
VPEN –
V-port data enable.
VVS –
V-port Vertical Synchronization.
VHS –
V-port Horizontal Synchronization.
VFILED –
V-port Even/Odd frame indicator.
DDERST –
Output to DMD driver BD as RESETZ signal for DMD normal operation.
POWERON –
Output to power to enable the other power source (12V, 3.3V, VCC) into normal working situation.
Under power off status , there is only VCCCPU .
LAMPON –
Input signal as an indicator that the Lamp is ON or OFF.
LED0~3 –
Output to Keypad BD to enable the LED ON or OFF.
IRRCVR0 –
System IR input to CPU as remote control signals.
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