6 Special Circuit Descriptions
6-8
SAM4S ER-600 SERIES
6-5 Keyboard Circuit
The Key Board Circuit consist of the scan signal of 14 lines and the return signal of 7-line. The CPU sends repeatedly and
continuously the scan data S0 S
∼
15 through the 74HCT138(U1,U24). The key information input in the return signal if
the specific key is pressed during the given time. The CPU reads the data through U7(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 U7(74HC541) and performs
the selected
function.
Figure 6-10 Keyboard Block Diagram
DATA[0:7]
74HCT541
ADDR[0:4]
CPU (M30800SFP)
98 KEYS
Pull-Up
COMMON PORT
•
•
•
•
•
•
•
MODE KEY
•
•
•
•
•
•
•
•
ADDRESS DECODER(74HC138)
DIODE( MMBD6050L *16)
ADDRESS DECODER
(74HC138)
CS1, ADDR[11:13], nRESET
KBD_CS
Summary of Contents for ER-600
Page 48: ...8 Exploded Views and Parts List 8 6 SAM4S ER 600 SERIES MEMO...
Page 54: ...9 PCB Layout and Parts List 9 6 SAM4S ER 600 SERIES MEMO...
Page 55: ...SAM4S ER 600 SERIES 10 1 10 Block Diagram 10 1 ER 600...
Page 56: ...10 Block Diagram 10 2 SAM4S ER 600 SERIES MEMO...
Page 58: ...11 Wiring Diagram 11 2 SAM4S ER 600 SERIES 11 2 Wiring Diagram Figure11 1 Wiring Diagram...
Page 68: ...Shin Heung Precision FEBRUARY 2004 Printed in KOREA V1 1 Code No JK68 60935A...