gprs module serial port

Forum 2005-2010 (read only) Hardware Interfacing
1

hello, i am using a gprs module, i worked perfectly, but suddenly it stopped transmiting to my computer. I can transmite from the computer to the gprs but not in the other way.

is it possible that the microprocessor is broken?

Thanks , regards

2

is it possible that the microprocessor is broken

It is possible but not very probable.

Most likely is you connections, software or at a pinch the serial buffer chip.

3

Thanks for ask me.

I connected the module (Vcc = 3.3 V) with my own circuit, with Vcc = 5v, i am thinking that perhaps it is a problem. What do you think?

regards

4

i am thinking that perhaps it is a problem

Yes connecting 3v3 equipment up to 5V is a good way to destroy it.
Did you connect the supplies like this?

The output signal of 3V3 will be OK to connect to the input of 5V signals (providing you only pull up to 3v3 and not 5V)

However input signals of 5V need converting before you feed them into the input of a 3v3 system.

5

i agree with you, but i thought it too late...

However, the problem is with the transmiter in the gprs, it is an output in the module, the receiver works perfectly, because i can make calls, and this is the input in the module.

how can it be posible????

another cuestion, if i dont connect anything to the TX and RX, i see 0 V, but, the protocol says that it must be "1"(3.3V)... is it another problem?

Thanks