Panasonic KX-FT982CA / KX-FT984CA / KX-FT988CA Service Manual ▷ View online
17
KX-FT982CA-B / KX-FT984CA-B / KX-FT988CA-B
Connection to operation reset circuit
104
STB2
O
3.3V
STROBE SIGNAL OUTPUT TO THERMAL HEAD
105
STB3
O
3.3V
OUTPUT PORT (NC)
106
XRESET
I
3.3V
RESET INPUT
107
VDD (3.3V)6
-----
POWER SOURCE (+3.3V)
108
VSS8
GND
POWER SOURCE (GND)
109
VSS9
GND
POWER SOURCE (GND)
110
VDD (3.3V)7
-----
POWER SOURCE (+3.3V)
111
XORESET
O
3.3V
NOT USED
112
VDD(5V)
-----
POWER SOURCE (+5V)
113
VSS10
GND
POWER SOURCE (GND)
114
XRESETI
I
3.3V
RESET INPUT
115
XWDERR
O
3.3V
WATCHED ERROR OUTPUT SIGNAL
116
THDAT
O
3.3V
RECORDED IMAGE OUTPUT (THDAT)
117
THCLK
O
3.3V
CLOCK OUTPUT FOR DATA TRANSFER (THCLK)
118
THLAT
O
3.3V
PULSE OUTPUT FOR DATA LATCH (THLAT)
119
STBNP
I
3.3V
INPUT PORT (MOT-POS)
120
RM0/IOP
O
3.3V
MOTOR A PHASE
121
RM1/IOP
O
3.3V
MOTOR B PHASE
122
RM2/IOP
O
3.3V
MOTOR /A PHASE
123
RM3/IOP
O
3.3V
MOTOR /B PHASE
124
RXE/IOP
O
3.3V
MOTOR ENABLE
125
TMO
O
3.3V
OUTPUT PORT (R1)
126
VDD (2.5V)4
-----
POWER SOURCE (+2.5V)
127
VSS11
GND
POWER SOURCE (GND)
128
TM1/IOP
O
3.3V
OUTPUT PORT (R2)
129
TM2/IOP
O
3.3V
OUTPUT PORT (CISON)
130
TM3/IOP
O
3.3V
OUTPUT PORT (RLY)
131
TXE/IOP
I
3.3V
INPUT PORT (CUT_POS)
132
KSTART
O
3.3V
OPERATION PANEL CONTROL
133
KLATCH
O
3.3V
OPERATION PANEL CONTROL
134
KSCLK
O
3.3V
OPERATION PANEL CONTROL
135
KTXD
O
3.3V
OPERATION PANEL CONTROL
136
KRXD
I
3.3V
OPERATION PANEL CONTROL
137
FMEMCLK/IOP
O
3.3V
OUTPUT PORT (OPRESET)
138
FMEMDI/IOP
O
3.3V
OUTPUT PORT (NC)
139
ADSEL1
O
3.3V
CHANNEL SELECT SIGNAL FOR AIN2
140
VDDA (2.5V)
2.5V
POWER SOURCE (ANALOG +2.5V)
141
VREFB
A
3.3V
A/D CONVERTER'S ZERO STANDARD VOLTAGE
OUTPUT
OUTPUT
142
VCL
A
3.3V
ANALOG PART STANDARD VOLTAGE SIGNAL
143
VREFT
A
3.3V
A/D CONVERTER'S FULL SCALE VOLTAGE OUTPUT
144
VSSA2
GND
POWER SOURCE (ANALOG GND)
NO.
SIGNAL
I/O
POWER SUPPLIED
VOLTAGE
DESCRIPTION
18
KX-FT982CA-B / KX-FT984CA-B / KX-FT988CA-B
6.3.2.
Flash Memory (IC2)
This 512KB ROM (FLASH MEMORY) carries a common area of 32KB and bank areas which each have 8KB (BK4~BK63). The
addresses from 0000H to 7FFFH are for the common area and from 8000H to 9FFFH are for the bank areas.
addresses from 0000H to 7FFFH are for the common area and from 8000H to 9FFFH are for the bank areas.
6.3.3.
Dynamic RAM (IC4)
The DRAM serves as CPU and receives memory.
The address is F200H~F3FFH (DRAM access window 1) and F600H~F7FFH (DRAM access window 2).
The address is F200H~F3FFH (DRAM access window 1) and F600H~F7FFH (DRAM access window 2).
6.3.4.
Reset Circuit (Watch dog timer)
The output signal (reset) from pin 4 of the voltage detect IC (IC3) is input to the ASIC (IC1) 114 pin.
1. During a momentary power interruption, a positive reset pulse of 50~70 msec is generated and the system is reset com-
pletely.
2. The watch dog timer, built-in the ASIC (IC1), is initialized by the CPU about every 1.5 ms.
When a watch dog error occurs, pin 115 of the ASIC (IC1) becomes low level.
The terminal of the 'WDERR' signal is connected to the reset line, so the 'WDERR' signal works as the reset signal.
The terminal of the 'WDERR' signal is connected to the reset line, so the 'WDERR' signal works as the reset signal.
19
KX-FT982CA-B / KX-FT984CA-B / KX-FT988CA-B
6.3.5.
RTC Back up Circuit
1. Function
This unit has a lithium battery (BAT1) which works for the Real Time Clock (RTC, Integrated into ASIC:IC1).
The RTC continues functioning, even when the power switch is OFF, backed up by a lithium battery.
The RTC continues functioning, even when the power switch is OFF, backed up by a lithium battery.
2. Circuit Operation
When the power is turned ON, power is supplied to RTC (IC1).
At this time, the voltage at pin 14 of RTC (IC1) is +3.3V. When the power is turned OFF, the battery supplies the power to RTC
through JS1, R30, D14. At that time, the voltage at pin 14 of IC1 are about +2.5V. When the power is OFF and the +5V and
+3.3V voltages decrease, the LOW is input to pin 114 of IC1. Pin 111 of IC1 outputs the reset signals. Pin 11 of IC1 become
low, then RTC (IC1) go into the back up mode, when the power consumption is lower.
At this time, the voltage at pin 14 of RTC (IC1) is +3.3V. When the power is turned OFF, the battery supplies the power to RTC
through JS1, R30, D14. At that time, the voltage at pin 14 of IC1 are about +2.5V. When the power is OFF and the +5V and
+3.3V voltages decrease, the LOW is input to pin 114 of IC1. Pin 111 of IC1 outputs the reset signals. Pin 11 of IC1 become
low, then RTC (IC1) go into the back up mode, when the power consumption is lower.
20
KX-FT982CA-B / KX-FT984CA-B / KX-FT988CA-B
6.3.6.
Supervision Circuit for the Thermal Head Temperature
1. Function
The thermistor changes the resistor according to the temperature and uses the thermistor's characteristics. The output of pin
139 of IC1 becomes a low level. Then when it becomes a high level, it triggers point A. In point C, according to the voltage
output time, the thermal head's temperature is detected.
After the thermal head temperature is converted to voltage in B, it is then changed to digital data in the A/D converter inside
IC1. The CPU decides the strobe width of the thermal head according to this value. Therefore, this circuit can keep the ther-
mal head at an even temperature in order to stabilize the printing density and prevent the head from being overheated.
139 of IC1 becomes a low level. Then when it becomes a high level, it triggers point A. In point C, according to the voltage
output time, the thermal head's temperature is detected.
After the thermal head temperature is converted to voltage in B, it is then changed to digital data in the A/D converter inside
IC1. The CPU decides the strobe width of the thermal head according to this value. Therefore, this circuit can keep the ther-
mal head at an even temperature in order to stabilize the printing density and prevent the head from being overheated.
REFERENCE:
Thermal Head (P.23)
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