Cameron KS21TK305A, Руководство по обслуживанию

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SERVICE MANUAL
26
There are three methods of exiting power down:
•
The first method to wake up from Power-Down is to use one of these two external interrupts: EX0
and EX1. The interrupt EX2 cannot be used to wake up the system. Since the clock is stopped, these
external interrupts needs to be set level sensitive before entering Power-Down. The interrupt is
serviced, and following the instruction RETI, the next instruction to be executed will be the one
after the instruction that put the device into Power-Down mode.
•
A second method to exit Power-Down is via an interrupt triggered by the SAD DC comparator.
This can be used e.g. to trigger a wake-up of the device by TV Front Panel key-press. As above, the
interrupt is serviced, and following the instruction RETI, the next instruction to be executed will be
the one following the instruction that put the device into Power-Down
•
The third method of terminating the Power-Down mode is with a Power On reset. Reset defines all
SFRs and Display memory, but maintains all other RAM values. Code execution commences with
the Program Counter set to
“
0000
”
.
1.6.2.4 General recommendations
In power saving application modes where all three external interrupts are required the Idle
mode must be used. The difference between the Power Down mode and the Idle mode in terms of
power is quite small since they only differ in the amount of peripherals kept operational. The
purpose of these peripherals is to provide the interrupt request signals to wake up the micro
controller.
1.7 Display Engine
The display section reads the contents of the Display memory and interprets the
control/character codes. From this information and other global settings, the display produces the
required RGB signals and Video/Data (Fast Blanking) signal for a TV signal processing device.
The display is synchronized to the TV signal processing device by way of Horizontal and
Vertical sync signals generated in UOCIII. From these signals the display timing is derived.
Display Block Diagram
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