I know it´s the approximately 1000. post for problems with GM862 in this forum, but alltough my problem is quite new, i guess…
I´m using a GM862-Quad module connected to a ATMEGA164.
The problem is that the gsm module doesn´t power up anyway. I pulled the ON/OFF pin down for 0.5-5secs put it doesn´t come up. Unfortunately i missed to connect the PWRMON line to the board so it´s hard to measure this pin, but the status led should do it anyway… i hope
Reading all the threads here in the forum brought me to think about the following things:
1.) Must the pins 4 & 6 be connected to ground if unused?
2.) Must the case be soldered down to ground?
3.) Will the GSM module startup even if the TXD/RXD lines are not correctly initialized?
I don´t think that the problem is the supply voltage, as i use a 3A regulator, and i use 2x 100µF MLCC directly at the VCC pins (i also monitored the voltage at the GM862 when trying to switch it on and it seemed to be very stabled at ~3.95V).
So if anyone could answer my questions or give me another tipp how to manage the module to power on i would be very thankful.
i have already read this blog before. but now i figured the problem out… i connected the reset pin directly to the atmega and set it to “1” instead of tristate…
There are many ways to find out if your GSM module is up. First of all You may check GSM Tx line - it should be appr 2.85 V if module is ON. Just read it as a General purpose I/O.
The more interesting think is what happens with GM862. You may check if the connector is properly soldered. There you may have some unsoldered pins that are hard to find. Check the lines that are the inputs for GM862. It’s a good practice to not apply any voltage on the until the module starts. Also no line may have more than 3.3 volts. Telit modules are not 5 V compliant.
You may also check the power switch voltage when switch is open - it should be above 2.5 V.