Function

Power supply measurement (up to 3.84 V)

Purpose

Battery check

Syntax

uns8 getSupplyVoltage()

Parameters

 –

Return value

level = 1, 2, …59                   Voltage [V] = 261.12 / (127 - level)

Output values

 –

Preconditions

 –

Remarks

•     The internal power supply voltage is checked.

•     In the case of TR modules with LDO, it is the LDO output but not the actual battery voltage. This value is 3.0 V typically if the battery is O.K. and drops down if the battery is low.

•     To evaluate the battery, take into consideration your battery type and power supply circuitry with respect to diodes and other possible voltage drops.

Side effects

A/D converter control registers are changed.

See also

  –

Example

if (getSupplyVoltage() < 38)

    …                             // Low battery

else

    …                             // Voltage > 2.93 V