122 FC1 I Switch 1 for function selection.
123 SDO O RS232 compliant serial data output.
124 C+ O Positive capacitor connection for on-chip DC-DC converter.
125 C- O Negative capacitor connection for on-chip DC-DC converter.
126 V- P Negative supply voltage. Connecting to 3V battery negative terminal.
127 V- P Negative supply voltage. Connecting to 3V battery negative terminal.
128 LBAT9 I Low battery configuration. If 3V battery is used, connect it to AGND
The default low-battery threshold voltage is –2.3V. If 9V battery is
Used, the low battery annunciator is displayed when the voltage of
this pin is less than VRH (-1.2V)