Memory - Sony VPL-PX20 Service Manual

2. USB Projector Controller IC: IC3304 ST72T36
In the USB communication between the personal computer and main MPU of the projector, the
enable signal: Low (IC3303;#42) of the microprocessor cable hub for performing protocol conversion
(USB-IC) is input to the Q3310 base, Q3310 goes OFF, this IC#8 becomes high, and reset is
canceled.
The projector control signal executed by the application projector station for the projector on the
personal computer is input to IC31 and IC32 via the HUB (IV3303). This signal is analyzed and sent
to the main MPU by IIC (#24, #28).
Basically, this IC is the master while the main MPU is the salve.
To send the projector information (input signals, etc.) to the personal computer, the main MPU
converts the signal line USB REQ to Low. When this signal is input to #7, this IC requests for
projector information using IIC to the main MPU.
3. IrDA Circuit
The remote control signal (IrDA) received by the infrared photo-sending unit (NF/NR M't) in front
and at the back of the projector is input to the IrDA filter IC (IC3301) (NF;#2, NR;#3). In IC3301, the
photo-sensing unit effective signal (NF;#7, NR;#6) by the main MPU is enabled = low, and the signal
determined as a useful IrDA signal is output from #5. While it is input as the SIRCS signal to the
main MPU via the SIRCS circuit (QD), it is input to #1 of IC3302 (#2 is fixed at low), the reverse
signal is output from #7, input to #2 and 6 of IC3002, and #7:IrDA, #3:IrDB are output to the QB
board and QC board,
If INPUT-A is selected, the control signal mouse A/B becomes high by the main MPU, and
consequently, #1 of IC3002 becomes high (#5:Low), the IrDA signal is output only from #7, and #3
is prohibited.

3-5-3. Memory

Memory structure of VPL-PX20/30 series is based on the 600 series, and it is composed of the following
five memory blocks.
1. Set memory
2. Status memory
3. Channel memory
4. Chroma memory
5. W/B memory
The 600 series is equipped with the gamma memory, but the current VPL-PX20/30 series is no gamma
memory. The gamma mode function is realized by applying the offset to the output value of the contrast
and the brightness of the devices as X2000 series.
When the power plug is connected to the power line (Standby status), all data inside the internal ROM are
written into the NVM (Nonvolatile Memory). When the power is turned on, required data for the current
picture, such as status memory data, etc., are selected, and they are written into the internal RAM.
When adjustment is carried out, adjustment data are written into the NVM automatically (items on the
user mode) or by the trigger of memory operation (items on the service mode and special service mode).
Adjustable items (W/B and Device Adjust) of the service mode and special service mode are memorized
into the NVM by the memory operation. At the same time, the factory preset (adjusted) data are all
eliminated from the memory.
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VPL-PX20/PX30