Mode Key Switch Status Read - Casio 200CR Service Manual

Pin No. Signal
55 P123 Display segment signal (SEG0d) / Key common singnal (KC2)
56 P124 Display segment signal (SEG0e ) / Key common singnal (KC1)
57 P125 Display segment signal (SEG0f) / Key common singnal ( KC0)
58 P126 Display segment signal (SEG0DP)
59 P127 Display segment signal (SEG0g)
60 RESET Reset signal (RESET)
61 P00 Timing pulse from printer (TP)
62 P01 TAX switch (TAX-SW ) / PAD condition signal (PAD2)
63 P02 Power down signal (PWD)
64 P03 Display common signal (DG1)
65 P04 Display common signal (DG2)
66 P05 Display common signal (DG3)
67 P06 Display common signal (DG4)
68 VDD VDD terminal (VDD)
69 X1 Main system clock signal (5.00 MHz)
70 X2 Main system clock signal (5.00 MHz)
71 IC Vss (GND)
72 XT2 Sub system clock signal (32.768 kHz)
73 XT1 Sub system clock signal (32.768 kHz)
74 AVDD Power for A/D converter (VDD)
75 AVREF0 Standard voltage for A/D converter (VCC)
76 P10 Low battery signal (LOW-BATT)
77 P11 Mode key condition signal (MODE)
78 P12 OFF signal of mode switch (OFF-MODE IN)
79 P13 PAD condition signal (PAD1)
80 P14 Display segment signal (SEGTR ) / PAD condition signal (PAD3)
Note : The "PW-on level" was measured under the following conditions.
Mode switch is REG position.

5-3. Mode key switch status read

The CPU knows the mode swithc status by voltage level of 1 pin No. 77.
The voltage level is down by resistor. Each voltage is as shown bleow.
Voltage level (pin No. 77 of CPU)
Mode PRG
Voltage (V) 4.0
Mode OFF¤
Voltage 0
Description
RF REG
3.3 2.4
except
→
OFF (pin No. 78 of CPU)
5
To pin No.77
To pin No.78
— 13 —
In / Out
In / Out
CAL X
1.7 0.9
20K
8.2K
3.9K
2K
820
P W - O N
l e v e l
Out Pulse
Out Pulse
Out Pulse
Out Pulse
Out Low
In High
In High
In Low
In Low
Out Pulse
Out Pulse
Out Pulse
Out Pulse
— 4.5 V
In Pulse
In Pulse
— GND
In Pulse
In Pulse
— 5 V
— 5 V
In High
In 2.4 V
In High
In Low
Pulse
Z
0.1
PRG
RF
REG
CAL
X
Z
OFF