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4. Power Supply Control
The 8-bit microprocessor controls the power supply for the overall system.
The following is a description of how the power supply is turned on and off. When the battery is attached, a regulated 3.3 V
voltage is normally input to the 8-bit microprocessor (IC301) by IC303, so that clock counting and key scanning is carried out
even when the power switch is turned off, so that the camera can start up again. When the battery is removed, the 8-bit micro-
processor operates in sleep mode using the backup capacitor. At this time, the 8-bit microprocessor only carries out clock
counting, and waits in standby for the battery to be attached again. When a switch is operated, the 8-bit microprocessor supplies
power to the system as required.
The 8-bit microprocessor first sets both the P (A) ON signal at pin (70) and the P ON signal at pin (71) to low, and then turns on
the DC/DC converter. After this, High signals are output from pin (97) so that the ASIC is set to the active condition. If the LCD
monitor is on, the LCD ON signal at pin (95) set to Low, and the DC/DC converter for the LCD monitor is turned on.
Power voltage
Lens cover close
Power switch ON-
Lens
Shutter switch ON
cover
Resolution, Flash,
open
Self timer switch ON
Playback
Power voltage
Lens cover close
Power switch ON-
Lens
cover
open
Continuous image
Message from host
Note) P. SAVE = Power save mode, 4 MHz = Main clock operation, 32 kHz = Sub clock operation
Auto power down
LCD finder
Table 4-3. Camera Mode (Battery Operation)
Auto power down
Take a picture
Erase image
Download image
Table 4-4. Host Mode (Battery Operation)
ASIC,
RS232C
memory
driver
5 V (A), -7.5 V,
3.3 V
3.3 V
+15 V etc.
OFF
OFF
OFF
OFF
ON
ON
ON
OFF
OFF
ON
ON
ON
ON
ASIC,
RS232C
memory
Driver
5 V (A), -7.5 V,
3.3 V
3.3 V
+12 V etc.
OFF
OFF
OFF
OFF
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
8bit
MODE
CCD
LCD
CPU
3.2 V
3.2 V
(ALWAYS)
(ALWAYS)
OFF
32KHz
OFF
OFF
4MHz
OFF
4MHz
OFF
4MHz
ON
4MHz
OFF
4MHz
MODE
8bit
CCD
LCD
CPU
3.2 V
3.2 V
(ALWAYS)
(ALWAYS)
OFF
32 KHz
OFF
OFF
4 MHz
OFF
4 MHz
OFF
4 MHz
OFF
4 MHz
ON
4 MHz
ON
4 MHz
LCD
MONITOR
5V (L), 15 V,
+12V etc.
OFF
ON
OFF
ON
OFF
ON
OFF
ON
ON
ON
ON
LCD
MONITOR
5 V (L)
+12V etc.
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
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