Could not power on GM862 Cellular Quad Band Module with GPS

GPS/GNSS Development Boards
1

I have bought GM862 Cellular Quad Band Module with GPS but as newbi could not power it on.

Here it is what I did:

  • connected VBATT and GND to 3.7 Polymer Lithium Ion Batterie

  • connected pin 39 STAT_LED to LED in series with 100 Om resistor to +3.7 on th batterie

  • touching pin 17 ON/OFF to the GND for few seconds, trying to pull it up for few second and GND after that

I expected pulling up ON/OFF and put it to the GND should power the device so the STAT LED should give me indication of the network status but it is no lighting.

Please advice:

  1. How could I see if the device powered on? Need to pass this step before connecting TX RX I guess…

  2. Should the STAT LED give me an indication the device status? Did I connect it right?

Please help I have very little experience with hardware and got this module to support my software project on the microcontroller.

thanks.

2

To power on the module you must pull the ON# line to ground for at least 1 second and then release it. You can check the START line to see if the module has powered-up. The NETWORK LED will also start blinking to indicate the connection status.

I recommend using a 330 ohm resistor in series with the LED.

A couple of notes from the Telit hardware manual:

NOTE: don’t use any pull up resistor on the ON# line, it is internally pulled up. Using pull up resistor may bring to latch up problems on the GM862-QUAD power regulator and improper power on/off of the module. The line ON# must be connected only in open collector configuration.

TIP: To check if power has raised it is possible to monitor the START line, when this line goes high the module is powered on, but before it remains on the device needs other 900 ms for software startup. Hence check the PWRCTL line and 900 ms after its transition to high it is possible to release the ON# pin.

3

Gsm Man:
To power on the module you must pull the ON# line to ground for at least 1 second and then release it. You can check the START line to see if the module has powered-up. The NETWORK LED will also start blinking to indicate the connection status.

I recommend using a 330 ohm resistor in series with the LED.

A couple of notes from the Telit hardware manual:

NOTE: don’t use any pull up resistor on the ON# line, it is internally pulled up. Using pull up resistor may bring to latch up problems on the GM862-QUAD power regulator and improper power on/off of the module. The line ON# must be connected only in open collector configuration.

TIP: To check if power has raised it is possible to monitor the START line, when this line goes high the module is powered on, but before it remains on the device needs other 900 ms for software startup. Hence check the PWRCTL line and 900 ms after its transition to high it is possible to release the ON# pin.

The START line and PWRCTL both stay low.

The ON# line is low even when nothing is connected. The board is powered, but ON# and RESET# both stay low even if they are floating. Since they have internal pullup shouldnt they both float high after poweron?

Also, the case of the GSM module is not soldered into the red development board. It is plugged in firmly, but not soldered. Is it a requirement to solder the case posts? If so, will soldering only 1 suffice for initial testing?

Thanks :slight_smile: