User's Manual Part 1

MC75 Hardware Interface Description

Strictly confidential / Draft

MC75_V00.190a Page 23 of 91 15.02.2005

3.1.2 Measuring the Supply Voltage V

BATT+

The reference points for measuring the supply voltage V

BATT+

on the module are BATT+ and

GND, both accessible at a capacitor located close to the board-to-board connector of the

module.

Figure 4: Position of the reference points BATT+ and GND

3.1.3 Monitoring Power Supply by AT Command

To monitor the supply voltage you can also use the AT^SBV command which returns the

value related to the reference points BATT+ and GND.

The module continuously measures the voltage at intervals depending on the operating

mode of the RF interface. The duration of measuring ranges from 0.5s in TALK/DATA mode

to 50s when MC75 is in IDLE mode or Limited Service (deregistered). The displayed voltage

(in mV) is averaged over the last measuring period before the AT^SBV command was

executed.

Reference

point

BATT+

Reference

point GND