Epson PhotoPC 2100Z, Service Manual

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PhotoPC 2100Z Revision A
Operating Principles Overview 39
2.1.2 Operating Principles of Control Circuit
This section describes the functions of major elements constituting the circuitry of this
camera. The electric circuit of this camera is controlled by two CPUs, namely, the main
CPU and the 8-bit CPU.
Table 2-1. Peripheral Elements of Main CPU
Major Element Functions
CCD Matsushita MN39471JT
†
Converts the image formed on the CCD by the lens into an
electrical signal.
†
1/2.6 inches, 2,310,000 pixels, complementary color filter,
interline transfer
Timing Generator (TG) Matsushita MN5296-1
†
This IC generates various drive waveforms to be given to the
CCD.
V Driver Matsushita MN31121SA
†
This IC drives the vertical transfer register of the CCD.
CDS & A/D Analog Devices AD9843A
†
Converts analog signals given from the CCD into 10-bit digital
signals.
†
Incorporates a correlation double sampling circuit (CDS) to
remove the reset noise which can occur specifically with CCD.
Main CPU Texas Instruments TMS320DSC21GHK
†
CPU and peripheral functions integration chip for digital camera
†
Signals for CCD, SDRAM controller, flash memory,
CompactFlash, USB, and video system interface are integrated.
†
At shooting, writes the digital data from the CCD circuit in
SDRAM and after image processing of the written data followed
by image compression, writes in the CompactFlash.
†
At playback, this CPU reads the data from the CompactFlash and
decompresses it, develops the image into DRAM and generates
the signal to send the image to the LCD by the Video Controller.
†
The CPU reads the program written in the flash memory, and
operates according to the program.
†
27MHz and 48MHz crystal oscillators are connected to the
oscillating circuit.
SDRAM HYUNDAI HY57V653220BTC-10
†
Connected to the main CPU and used as the buffer memory for
image data, buffer memory for video data and memory for
program running.
Flash Memory Sharp LHFA8E09
†
The program of the main CPU is written in.
†
Some area is used to record camera information.
CompactFlash Records taken pictures.
LCD Controller EPSON EM1811D
†
Based on the video signal generated by the main CPU, the LCD
controller generates various signals which are necessary to drive
the LCD.
Color LCD Unit EPSON L2B1600-B002
†
1.6-inch collar LCD, with backlight
†
237 (horizontal)
×
234 (vertical) pixels
Table 2-2. Peripheral Elements of 8-bit CPU
Major Element / Unit Functions
8-bit CPU UPD780055GK-A11
†
Detects the operations of all the switches for user interface
excepting the Release switch, controls all the LEDs, buzzer,
flash, shutter, focusing, zooming, battery check and DC-DC
converter (main power supply), and has a clock function.
†
Executes the above control by communication with the main
CPU.
Shutter †
This shutter works also as the diaphragm.
†
Incorporated in the lens barrel.
†
Driven by the shutter driver LB1939T.
†
Controlled by the SMD__IN1, SMD_IN2 and SMD_EMA
signals from the 8-bit CPU.
Table 2-1. Peripheral Elements of Main CPU (continued)
Major Element Functions