NEC LCD1501-BK Service Manual page 60

CIRCUIT DESCRIPTION
TABLE OF CONTENTS
1. Block diagram ...................................................................................................................... 7-2
2. power circuit ......................................................................................................................... 7-3
2.1 power input ........................................................................................................................ 7-3
2.2 DC to Dc circuit .................................................................................................................. 7-3
2.3 panel Vcc control ............................................................................................................... 7-3
3. Microprocessor control circuit .............................................................................................. 7-4
3.1 clock circuit ........................................................................................................................ 7-4
2
3.2 I C buses ............................................................................................................................ 7-4
3.3 General-purpose port ......................................................................................................... 7-4
3.3.1 Key scan status ............................................................................................................... 7-4
3.3.2 scaler control ................................................................................................................... 7-4
3.3.3 Led control ...................................................................................................................... 7-4
3.3.4 Data memory .................................................................................................................. 7-4
4. Scaler ................................................................................................................................... 7-4
7-1
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