Hardware design
SPBT2632C2A
20/27
Doc ID 022833 Rev 4
7.6
External LPO input circuit
An optional low power oscillator input may be added to allow Deep sleep and Sniff modes.
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LPO parameters:
–
Frequency: 32.768 kHz
–
Tolerance: 150 ppm
–
Voltage levels
–
Low: 0.5 V
–
High: 1.8 V
–
Input capacitance: 2.5 pF maximum
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Configurations:
–
Use two configuration variables: UseExtLPO and AllowSniff.
Figure 11.
External LPO circuit
Table 9.
System configuration variables
Variable
Name
Default
Description
Var37
UseExtLPO True
True when a 32.768 kHz low power oscillator is present, and false
if not present
Var43
AllowSniff
True
Enables Sniff mode.
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