— 6 —
6-3. Printer drive circuit
When the CPU start printing, CPU send MD signal to rotate motor unit.
Then the printer send back the RP(reset pulse),PT and PT (Timing pulse) to CPU.
After CPU receive RP,Pt and PT, CPU knows the position of print wheel.
And then, CPU send HD signal to operate the printing magnet when the character selected.
The CPU counts the TP signal to select the character.
6-4. Pin description (CPU uPD78044AGF)
CPU
Pin No.44
Pin No.45
Pin No.47
Pin No.62
Pin No.63
RP
Pt
PT
MD
HD
Printer M42
Pin No.
Signal
In/Out
Mode SW
REG
Mode SW
OFF
AC cord
Plug off
Description
1 P94/FIP6
Out
Pulse
-24V
L
Display digit signal DG7
2 P93/FIP5
Out
Pulse
-24V
L
Display digit signal DG6
3 P92/FIP4
Out
Pulse
-24V
L
Display digit signal DG5
4 P91/FIP3
Out
Pulse
-24V
L
Display digit signal DG4
5 P90/FIP2
Out
Pulse
-24V
L
Display digit signal DG3
6 P81/FIP1
Out
Pulse
-24V
L
Display digit signal DG2
7 P80/FIP0
Out
Pulse
-24V
L
Display digit signal DG1
8 VDD
-
+5V
+5V
+5V
VDD terminal
9 P27/SCK0
In/Out
-
-
-
Not used
10 P26/SO0/SB1 In/Out
-
-
-
Not used
11 P25/SI0/SB0
In/Out
-
-
-
Not used
12 P24/BUSY
In/Out
-
-
-
Not used
13 P23/STB
Out
H
H
H
Strobe signal for AVREF
14 P22/SCK1
Out
L
H
H
SK signal for EEPROM
15 P21/SO1
Out
L
H
H
DI signal for EEPROM
16 P20/SI1
In
H
H
H
DO signal for EEPROM
17 RESET
In
H
H
H
Reset signal
18 P74
Out
H
H
L
Drawer open signal
19 P73
Out
L
H
H
Common signal for PAD condition
20 AVSS
-
GND
GND
GND
GND for AD converter
21 P17/ANI7
In
GND
GND
GND
GND
22 P16/ANI6
In
GND
GND
GND
GND
23 P15/ANI5
Out
L
L
H
Chip enable signal for EEPROM
24 P14/ANI4
In
GND
GND
GND
GND
25 P13/ANI3
In
GND
GND
GND
GND
26 P12/ANI2
In
GND
GND
GND
GND
27 P11/ANI1
In
GND
GND
GND
GND
28 P10/ANI0
In
H
H
H
Low battery detection terminal
29 AVDD
-
H
H
H
Power for AD converter
30 AVREF
In
L
L
L
Voltage for AD converter (VDD)
31 XT1
In
Pulse
Pulse
Pulse
Sub system clock
32 XT2
-
Pulse
Pulse
Pulse
Sub system clock
33 VSS
-
GND
GND
GND
GND
34 X1
In
Pulse
L
L
Main system clock
35 X2
-
Pulse
H
H
Main system clock
36 P37
In
L
L
L
Mode switch position (OFF)
37 P36/BUZ
Out
L
L
L
Buzzer signal
38 P35/PCL
In
L
L
L
Mode switch position (Z)
39 P34/T12
In
L
L
L
Mode switch position (X)
40 P33/T11
In
L
L
L
Mode switch position (CAL)
