KX-FT21RS
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 6MHz.
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.MODEM
Execute modulation and demodulation for the FAX.
5.ROM/RAM I/F
Controls the SELECT signal of ROM or RAM and bank switching.
6.CIS I/F
Controls document reading.
7.IMAGE DATA RAM
This is inside the ASIC and has 8KB which is used for image processing.
8.THERMAL HEAD I/F
Transmits the recorded data to the thermal head.
9.MOTOR I/F
Controls the motor which feeds the document and feeds the reading document.
10.OPERATION PANEL I/F
Serial interface with Operation Panel.
11.I/O PORT
I/O Port Interface (for analog board port control).
12.ANALOG UNIT
Electronic volume for the handset and monitor. Sends beep tones, etc.
Explanation of the Pin Distribution (IC1)
Pin | Pin Name | Buffer Power supply | 5V Tolerant | Signal Name | I/O | Description |
1 | X32OUT | VDDRTC | - | X32OUT |
| 32.768kHz oscillator for RTC |
|
|
|
|
|
| resistor) |
2 | X32IN | VDDRTC | NO | X32IN |
| 32.768kHz oscillator for RTC |
|
|
|
|
|
| resistor) |
3 | VDDRTC |
|
| +3.3V/BATT |
| 32.768kHz backup power supply for RTC |
4 | XBACKEN | VDDRTC | YES | XRESET |
| Backup enable |
5 | VDDSRAM |
|
| +3.3V/BATT |
| RAMCS buffer/backup power supply for reset |
6 | XRAMCS | VDDSRAM | - | VDDSRAM |
| SRAM chip select ("H": 3.3V or BATT) |
7 | XRAMCE2/ALARM | VDDSRAM | - | OPEN |
| Not used |
8 | FTG | MULT3/5 | NO | FTG | O | FTG |
9 | F1 | MULT3/5 | NO | F1 | O | F1 (50%/75% selector) |
10 | MULT3/5 |
|
| +5V |
| Power supply |
11 | VSS |
|
| DG |
| Ground |
12 | F2/OP50 | MULT3/5 | NO | E | O | LCD control |
13 | FR/OP51 | MULT3/5 | NO | OPEN | O | Not used |
14 | XRESET | 3.3V | YES | XRESET |
| Reset input for internal digital circuit |
15 | VSS |
|
| DG |
| Ground |
16 | XORESET | 3.3V | - | XORESET |
| Reset output |
17 | XRESETI | 3.3V | YES | XRESETI |
| Voltage detector IC output for reset |
18 | XWDERR | 3.3V | YES | XWDERR |
| Watch dog timer error |
19 | XRSTSWO/OP82 | 3.3V | YES | OPEN | O | Not used |
20 | VIDRST/IOP20 | 3.3V | YES | OPEN | O | Not used |
21 | SPHCLK/IOP21 | 3.3V | YES | OPEN | O | Not used |
22 | DARKON/IOP22 | 3.3V | YES | OPEN | O | Not used |
23 | ADSEL2/IOP23 | 3.3V | YES | OPEN | O | Not used |
24 | BELL/OP | 3.3V | YES | OPEN | O | Not used |
25 | 3.3V |
|
| +3.3V |
| Power supply |
