Cpu Circuit; Cpu - NEC MultiSync FP1350 Service Manual

6. CPU CIRCUIT

1) CPU

IC801: 8 bit CPU / CMOS IC
IC802: EEPROM / CMOS IC
IC571: I/O Expander
This system has the following functions.
Frequency Counter
2
I C BUS control
fH band
Degaussing Control
DAC control (see 2. DC Control Circuit)
PMS control (see 3. Power Management system (PMS) Circuit )
OSD control (see 5. User Control Operation)
a. Frequency Counter
IC801 counts Horizontal frequency by event counter, Vertical frequency by interval timer. Horizontal
sync is negative input to IC801 pin 4. Vertical sync is positive input to IC801 pin 36.
Sync range
Horizontal
Vertical
If Horizontal frequency is less than 1 kHz or Vertical frequency is less than 10 Hz, IC801 judges "NO
PULSE". And IC801 enters to "PMS MODE".
2
b. I C BUS control
CPU (IC801) controls the following ICs through I
DAC
PREAMP
2
E PROM
I/O EXPANDER
OSC IC(DSP)
OSD IC
SUB CPU
AUTO SIZE IC
31.0 - 115.0 kHz
55.0 - 160 Hz
2
C BUS.
IC751(M62393FP) IC532(M62392FP)
IC711(M52742ASP)
IC802(24LC08,M24C08)
IC571(M62320FP)
IC501(HE6-0092)
IC791(M35070-050FP)
IC851(MC68HC705BD32FU)
IC8M1(BU6483K)
8-21
IC8A1(24LCS21A)