– 8 –
ASIC,
memory
CCD
8 bit
CPU
LCD
MONITOR
Power voltage
Power OFF
Play back
Shutter switch ON
Monitor OFF
LCD finder
3.3 V
5 V (A)
+15 V (A) etc.
3.2 V
(ALWAYS)
+15 V (L)
OFF
OFF
32KHz OFF
OFF
OFF
4 MHz OFF
ON
ON→OFF
4 MHz OFF
OFF
OFF
4 MHz OFF
ON
ON
4 MHz ON
ON
OFF
4 MHz ON
Table 4-3. Camera Mode (Battery Operation)
Note) 4 MHz = Main clock operation, 32 kHz = Sub clock operation
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 3.2 V
voltage is normally input to the 8-bit microprocessor (IC301) by IC302, 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 lithium secondary battery. 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 (6) and the P ON signal at pin (5) to high, and then turns on the
DC/DC converter. After this, high signals are output from pins (60), (61), (62), (63) and (64) so that the ASIC is set to the active
condition. If the LCD monitor is on, the LCD ON signal at pin (21) and the LCD ON 2 signal at pin (53) set to high, and the DC/DC
converter for the LCD monitor is turned on. Once it is completed, the ASIC returns to the reset condition, all DC/DC converters
are turned off and the power supply to the whole system is halted.
Power switch ON-
Auto power OFF
CAMERA
5. 16-bit D/A circuit (Audio)
This circuit converts the audio signals (analog signals) from the microphone to 16-bit digital signals.
6. 16-bit A/D circuit (Audio)
The audio signals which were converted to digial form by the 16-bit A/D circuit are temporarily to a sound buffer and then
recorded in the SSFDC card. During playback, the 16-bit D/A circuit converts these signals into analog audio signals.
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