7-3
5. E
2
PROM for PnP (Circuit Diagram: Interface PWB)
6. E
2
PROM (Circuit Diagram: Interface PWB)
Data transfer between I305 (AT24 C16) and CPU by the IIC bus SCL (pin 15) and SDA (pin 16) of I302. The
data to be transferred to each device are stored in I305.
I315 control data.
OSD related setting data.
Other control data for service menu.
7. CPU Circuit (Circuit Diagram: Interface PWB)
I302 functions as the CPU.
The source voltage for the device is 5.0V and the system clock frequency is 24MHz.
7.1 Detection of POWER Switch Status
The I302 identifies the ON status of the two power supplies. The identification is made when the power
supply is turned off. For example, if the power supply is turned off with the POWER switch, the POWER
switch must be turned on when activating the power supply again. If the power supply is turned off by
pulling out the power cord, then this power supply can be turned on by connecting the power cord,
without pressing the POWER switch.
7.2 Display Mode Identification
7.2.1 Functions
(1) Display mode identification
The display mode of input signal is identified based on Table 1.
When the mode has been identified through the measurement of horizontal and vertical frequencies,
the total number of lines is determined with a formula of Horizontal frequency / Vertical frequency =
Total number of lines. Final identification can be made by examining the coincidence of the obtained
figure with the number of lines for the mode identified from the frequency. The boundary number of
lines in each mode is shown in Table 2.
When the detected frequency if the sync signal has changed, the total number of lines should be
counted even through it identified frequency in the same mode.
(2) Power Save Mode
The power save mode is assumed when the horizontal / vertical signals are as specified below.
If there is no horizontal sync signal input.
If there is no vertical sync signal input.
If the horizontal sync signal outside the measuring range of gm5020.
If the vertical sync signal outside the measuring range of gm5020.