Marius_IMV
Newbie level 6
Hello,
I'm designing a board for some GPRS communication. The module works fine so far but if I want to turn it OFF it wont stay OFF and after 10 sec it powers ON by itself. Also I cannot power it OFF from the power key pin, the only way is to send the AT+CPOWD=1 command. After this command it says NORMAL POWER DOWN, the STATUS led goes OFF, also the NETLIGHT stops blinking. After aprox 10 seconds STATUS goes ON, and I receive RDY and so on like normal power ON.
I should mention that I think I made some stupid things when testing the modem like pulling the power KEY pin directly to GND when trying to power it on even if in the HD file was a 1k resitor in series with the transistor. Also when I power it down the voltage on the power Key pin goes to zero (and that is not normal i think - measured with pin left floating).I tried to pun a 10k pull up resistor (when powered down) but the voltage is still zero (like something inside pulls it down). When it's ON the voltage goes to 2,8v (also with pin floating).
Anyone have any idea what is going on and what parts inside the modem that might be broken ? (Just curious ...) I'm happy that it stays On and not OFF because I can do some work but I want to know what I should avoid on the final design.
I'm designing a board for some GPRS communication. The module works fine so far but if I want to turn it OFF it wont stay OFF and after 10 sec it powers ON by itself. Also I cannot power it OFF from the power key pin, the only way is to send the AT+CPOWD=1 command. After this command it says NORMAL POWER DOWN, the STATUS led goes OFF, also the NETLIGHT stops blinking. After aprox 10 seconds STATUS goes ON, and I receive RDY and so on like normal power ON.
I should mention that I think I made some stupid things when testing the modem like pulling the power KEY pin directly to GND when trying to power it on even if in the HD file was a 1k resitor in series with the transistor. Also when I power it down the voltage on the power Key pin goes to zero (and that is not normal i think - measured with pin left floating).I tried to pun a 10k pull up resistor (when powered down) but the voltage is still zero (like something inside pulls it down). When it's ON the voltage goes to 2,8v (also with pin floating).
Anyone have any idea what is going on and what parts inside the modem that might be broken ? (Just curious ...) I'm happy that it stays On and not OFF because I can do some work but I want to know what I should avoid on the final design.