Geostar GeoS-3, Руководство пользователя

Страница: 7 / 13

© R&D Center “GeoStar navigation” Ltd. 2012-12-25 7
2.3.2
Power Plan
The board is powered with USB bus 5.0V voltage. There are two DC-DC converters to generate
two secondary voltages: 3.3V (switch regulator) and 1.8V (LDO). Li-Ion battery CR1220
(38mAh) is the source of backup voltage.
2.3.3
Serial Ports
GeoS-3 serial ports are converted to USB in USB
—RS232 FT2232 chip (FTDI). The chip’s
supply voltage 3.3V comes directly from DC-DC converter output so it is powered right after
USB port is attached to the active USB Host.
2.3.4
Connectors

Antenna : antenna port.
Type: MMCX female, straight.

Port #0 & #1 : USB port.
Type: USB type B.

1PPS : 1PPS output.
Signal levels are referred to VDD_IO.
Type: SMA female, right angle.
2.3.5
Switches, pushbuttons
Switches:

POWER : GeoS-3 power control.
Moving switch to ON turns the module on; moving switch to OFF removes the power.

Battery : backup voltage control.
If the switch is set to ON then the battery is connected to the module; when O FF , the
battery is disconnected.

VDD_IO : VDD_IO voltage select.
If the switch is set to 3.3V , then VDD_IO=3.3V. If the switch is set to 1.8V , then
VDD_IO=1.8V.
Pushbuttons:

ON/OFF : on/off control.
Pushing the button forces the module to “OFF” state.