Chapter 4. Hardware Description - Sharp XE-A101 Service Manual

CHAPTER 4. HARDWARE DESCRIPTION

1. OUTLINE
•
CPU: uPD780023A (ROM 24KB, RAM 1024B)
•
KEY BOARD: 30key including PF key
•
MODE SW: 5position slide SW
DISPLAY: 7seg.+DP x 8digit LED (YELLOW GREEN) FRONT only
•
DRAWER: 1ch, no open sensor
•
BUZZER: 1beep, piezo buzzer
•
PRINTER: M-31(no EURO SYMBOL)
2. BLOCK DIAGRAM
6V
AC POWER MA IN
5V
SUPPLY 4.19MHz
Printer
M-31
CPU
uPD 780023A
D RAWER
BU ZZER
3. DISCRIPTION
1) DISPLAY
ST4- ST3-
(Output Timing of STROBE signal)
1ms
30~100us
ST1-
ST2-
Display
strobe
ST3-
ST4-
For Clock
32.768kHz
FRONT display :8digit
ST1- ST4-,ST5
8. 8. 8. 8. 8. 8. 8. 8.
A1 G1,DP1,A2 G2 ~ ,DP2
KST1 KST8
KE Y
BOARD
KR1 KR6
&
MODE SW
Battery
5V
ST2- ST1-
2) KEYBOARD and MODE SW
MODE SW, KEY MATRIX is follows.
Note: Although the XE-A101 has 30 keys, the keyboard circuit is
actually 32 keys (+) the PF key.
POWER
OFF
REG VOID
1 2
SLIDE SW
22 26 1 2
31 7 8 9 10
15 16 17 18 19
24 25 27 28
1
2
3
4
5
KR2 KR6 KR5 KR4 KR3
6 7 13 25
1 2 8 14
11 12 19 9
17 18 3 23
28 24 20 10
30 26 21 4
32 22 15 5
29 31 27 16
KEYBOARD
3) BUZZER
The BUZZER is driven by the P75/BUZ signal of the CPU.
Frequency : 4.095kHz
X/F Z/PGM
3 4 5
3 4 5 6
11 12 13 14
21
30 32
SW1
KST2
KR1
KST3
KST4
KST5
MODE SW
KCN2
D13 1SS133 KST1
1
D14 1SS133 KST2
2
D15 1SS133 KST3
3
D16 1SS133 KST4
4
D17 1SS133 KST5
5
D18 1SS133 KST6
6
D19 1SS133 KST7
7
D20 1SS133 KST8
8
KST1
9