“Confidential, Do Not Duplicate without written authorization from NEC.”
8-2
CIRCUIT DESCRIPTION
PJKEY PWB Circuit Operation
1
Key
Connections are made for the 35 keys on the boards and the 4x5 key matrix for the CPU PWB.
If there is a 4x5 key matrix simply, only 20 keys can be disposed of. Therefore, using combination of the
following three CTL keys (double pressing), part of the key matrix is changed over.
LENS CTL key: (CTL key to operate the lens system)
MACRO CTL key: (CTL key for macro changeover)
LAMP CTL Key: (CTL key for lamp output and lamp ON/OFF operation)
This key matrix changeover is carried out in the hardware and this operation is in the exclusive relationship.
The backlight is also lit up for the key that becomes effective at the time of this key matrix changeover.
The backlight ON/OFF key is used for the backlight ON/OFF operation, including the LCD.
The LIGHT1 PWB for PJKEY PWB lighting and the LIGHT2 PWB for terminal block lighting are synchronized.
The backlight of invalid keys is kept unlit even when the backlight is lit in conjunction with the CTL key.
2
Memory
There is provision of a 4k-byte E2ROM that is connected to the CPU PWB through I2C.
This memory keeps the serial number and such information that is singular to the set.
The same memory is accommodated in the CPU PWB and the PJDIV PWB. Therefore, even though any
board is replaced, the previously mentioned information is made to be retained.
3
IR light receiver
A wireless remote IR light receiver is provided.
This light receiver becomes invalid in the case of wired remote.
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