Printer Drive Circuit; Pin Description - Casio PCR-255 Service Manual

6-3. Printer drive circuit

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