Panasonic KX-FT25LA, Service Manual

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6.3.2. ASIC (IC1)
This custom IC is used for general FAX operations.
1. CPU
This model uses a Z80 equivalent CPU operating at 8MHz.
Many of the peripheral functions are handled by custom designed LSIS. As a result, the CPU only needs to process the result.
2. RTC
Real time clock.
3. DECODER
Decodes the address.
4. ROM/RAM I/F
Controls the SELECT signal of ROM or RAM and bank switching.
5. CIS I/F
Controls document reading.
6. IMAGE DATA RAM
This is inside the ASIC and has 8KB which is used for image processing.
7. THERMAL HEAD I/F
Transmits the recorded data to the thermal head.
8. MOTOR I/F
Controls the motor which feeds the document and feeds the reading document.
9. OPERATION PANEL I/F
Control port for Operation Panel.
10. I/O PORT
I/O Port Interface (for analog board port control).
11. ANALOG UNIT
Electronic volume for the handset and TAM monitor.
Sends beep tones, etc.
Explanation of the Pin Distribution (IC1)
Pin No. Pin Name Buffer Power Supply Description Digital I/O
1 AIN1 Analog Analog video signal AIN1
2 AIN2 Analog Thermistor voltage AIN2
3 AIN3 Analog Thermistor voltage, etc. VREFB
4 AMON Analog Analog monitor OPEN
5 VSSB Ground for analog video processing GND
6 VDDB Power supply for analog video processing +3.3V
7 3.3V/BATT RTC backup power supply +3.3V/BATT
8 X32OUT 3.3V/BATT 32.768kHz crystal for RTC X32OUT
9 X32IN 3.3V/BATT 32.768kHz crystal for RTC X32IN
10 VSS Ground GND
11 XBACKEN 5V/BATT Backup enable XBACKEN
12 5V/BATT RAMCS buffer/Backup power supply for reset 5V/BATT
13 XRAMCS 5V/BATT SRAM chip selection SRAMCS
14 FTG 5V FTG FTG O/Z
15 F1 5V F1 (50%/75% selection) F1 O/Z
16 F2/OP50 5V F2/Output port selection E O
17 FR/OP51 5V FR/Output port selection RS O
18 CPC 5V CPC (also used as Input port) CPC I
19 5V Power supply for buffer +5V
20 VSS Ground GND
21 RVN 5V RVN (for both scanner encoder and input port) KIN0 I
22 IRDATXD/IOP81 5V TXD for IrDA/Input output port selection OPSEL O
23 IRDARXD/IOP80 5V RXD for IrDA/Input output port selection TEST (CISON) O
24 TXD/IOP30 5V UART/Input output port selection TELRXENB O
25 RXD/IOP31 5V UART/Input output port selection KIN1 I
26 XRTS/IOP32 5V UART/Input output port selection KIN2 I/O
27 XCTS/IOP33 5V UART/Input output port selection KIN3 I/O
28 MIDAT/IOP45 5V Cross point IC/Input output port selection MDMTXENB O
29 MICLK/IOP46 5V Cross point IC/Input output port selection TONE1ENB O
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KX-FT25LA