Help interface BenQ GSM Modem to IC16F62A

[aratti]

do you mean to place another 3k3 to PWON and Gnd?

Yes

if I use 3.3v to PIC16F628A will communicate well to the GSM module?

Yes

I tried to supply the mcu with 3.3v with blinking program on PortB.0 but using the voltage meter no deflection shown.

Did you disable brown-out reset feature?

Naturally if you use 3.3V you don't need the devider!


Cheers

Al.

[mbox]

sorry I've been away for awhile,been busy at work.

Did you disable brown-out reset feature?

Now it works great! I got to try it on with the GSM (wish me luck)
BTW I noticed that when I used USB to UART (Serial TTL) Converter... I did this to display data to my serial communicator, the power from PC provide 4.5v to my PIC. Funny because even I remove the 3.3v supply for the pic to run the blinky program, it still runs, I think the pc provides the voltage to keep it going.
Could this mean that if I Connect the GSM (3.3v) and connect a USB to UART it will provide 4.5v not 3.3v that could harm the GSM? Please give advice. I need the PC to see what I'm doing.

regards,
mbox

[aratti]

Could this mean that if I Connect the GSM (3.3v) and connect a USB to UART it will provide 4.5v not 3.3v that could harm the GSM?

Yes, You can safely obtain up to 100 mA from the USB port and use it to power your device. In case you will need 3.3 V you have to use a voltage regulator to drop it from 5V to 3.3 V

.... Please give advice. I need the PC to see what I'm doing.

If you want to connect your system to the PC via RS232 port then you should use a level translator as MAX3223, which will convert RS232 level to 3.3 V TTL and vice-versa. Without it you will fry your modem input line.

Cheers

Al.