7 Special Circuit Descriptions
7-6
SAM4S ER-380M/F SERIES
7-4 Keyboard Circuit
The Key Board Circuit consist of the scan signal of 8 lines and the return signal of 8-line. The CPU sends repeatedly and
continuously the scan data S0 S
∼
7 through the 74HCT138(U21). The key information input in the return signal if the
specific key is pressed during the given time. The CPU reads the data through U23(74HC541) and analyzes what key is
pressed and transmits this information to the CPU, then performs the selected function. The Key Board Circuit sends the
mode scan signal to the Key-lock switch and takes the return data through the U23(74HC541) and performs
the selected
function.
Figure 7-8 Keyboard Block Diagram
DATA[0:7]
74HCT541
(U23)
ADDR[0:3]
CPU (M30800SFP)
44 KEYS
Pull-Up
COMMON PORT
•
•
•
•
•
•
•
MODE KEY
•
•
•
•
•
•
•
•
ADDRESS DECODER(74HC138)
( U21 )
DIODE( MMBD6050L *8)
P10.3
Summary of Contents for ER-380F
Page 2: ......
Page 19: ...2 Product Specifications 2 12 SAM4S ER 380M F SERIES MEMO ...
Page 31: ...5 Maintenance and Adjustment 5 2 SAM4S ER 380M F SERIES MEMO ...
Page 39: ...6 Reference Information 6 8 SAM4S ER 380M F SERIES MEMO ...
Page 51: ...8 Troubleshooting 8 4 SAM4S ER 380M F SERIES ...
Page 54: ...8 Troubleshooting SAM4S ER 380M F SERIES 8 7 ...
Page 57: ...8 Troubleshooting 8 10 SAM4S ER 380M F SERIES MEMO ...
Page 73: ...9 Exploded Views and Parts List 9 16 SAM4S ER 380M F SERIES MEMO ...
Page 85: ...10 PCB Layout and Parts List 10 12 SAM4S ER 380M F SERIES MEMO ...
Page 89: ...12 Wiring Diagram 12 2 SAM4S ER 380M F SERIES MEMO ...
Page 105: ...13 16 SAM4S ER 380M F SERIES ...
Page 107: ...13 18 SAM4S ER 380M F SERIES MEMO ...
Page 109: ......
Page 110: ...ⓒ Shin Heung Precision March 2004 Printed in KOREA V1 0 Code No JK68 60955A ...