SNAD01B

8-CHANNEL 8-BIT ADC

Battery Monitoring (Channel 7 only)

ENCH[7]

to ADC

DI[7]

VSS

20k

10k

30k

VSS

Battery

ENCH[7]

VDD

VSS

CH[7]

PH&ENCH[x]

PL&ENCH[x]

Figure10 The circuit of the Input pad of Channel 7

1.While read ADC command is sent and channel 7 is selected, ADC can be used to monitor

the battery voltage.

3.The battery voltage is six times ADC measuring voltage. Thus, the measured result equals

to 1/6*battery voltage.

4.While channel 7 is set to the analog input mode, an input resistor (60k

Ω) exists from CH[7]

to VSS. To save unnecessary power consumption, CH[7] should be switch to digital input

type when CH[7] is not measured.

Note: CH[7] is different from the other 7 channels. The input voltage is reduced to 1/6 before it is sent

into ADC.

Version: 1.3

July 31, 2003

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