plz help! unable to query modem for w302

[rashmu]

unable to query modem for w302

Hello evryone..am a new member of this forum.I am a final year BE student doing project on microcontroller(8051) using GSM.Its called the remote notice board.We r using the sony erricson w302 mobile as modem.It supports the AT commands in PDU mode.We hav tested it using hyperterminal.We hav connected the mobile to microcontroller using its datacable and USB to RS-232 converter.But we r unable to get the response of the mobile in microcontroller.We r using flash magic and ride software to download the program to the controller and we r using the AT89C51 flash board for initial programming.Can anybody help me to proceed?Am not finding any way out and its a bit urgent.Thanking u in advance. plz Dont mind reading such a big query.I will be very eagerly waiting for a reply...

 

[VVV]

get hyperterminal recognize usb rs232

I have had trouble with USB-RS-232 converters. Is there a way to get clean RS-232 signals directly to the interface to the uC?

Did you actually probe the signal on the uC pin to see if it gets there? Check that and the baud rate.

Also, connect to the uC using Hyperterminal and get it to work that way first. This will eliminate all the other things inbetween and allow you to test your code.

 

[rashmu]

Re: plz help!

Hi..as suggested by u,I changed the baud rate of the mobile.It was actually 115200 and by connecting it to the hyperterminal,i changed it to 9600.The baud rate of 8051 is also the same...but i doubt whether this setting remains the same after removing the mob from PC.Also u hav told to try by connecting controller to hyperterminal.Can u olz tell me how is it done n what can be checked doing that?Also we just checked the TX n RX pin of controller after downloading the pgm n executing it.(MC was put in the bread board)We actually got high signals in both of them(approx 5 volts).From this can we conclude that we hav got the response frm the mobile?Will be waiting for reply..bye

 

[VVV]

Re: plz help!

From your reply I don't understand if anything worked.
Can you be more specific? Did you manage to establish communication between the uC and the modem?
Did the Hyperterminal connection work? This would help eliminate all issues associated with the USB-RS-232 converter.

 

[rashmu]

Re: plz help!

Ok..wat i actually did was,i connected the microcontroller and mobile using (from the mobile end)datacable,Female-female USB connector and the usb-rs-232 converter.We have mounted the MC on bread board and hav used max-232 also.We tested at the transmit pin for high signal indicating data transmission(command to mob)where we did get a high voltage (thats around 5v).Also we got the high voltage at the receive pin too.I doubt can we,by this assume that receive pin is high bcoz its receiving the response from mobile?One thing is that both the pins are high simultaneously,but we normally expect receive pin to be high after tx pin goes low...right?So can u plz tell me how do we make sure that both r communicating?Also r u sure we can use mobile as modem in this case?I am asking this bcoz mobile is not responding in any manner(like it responds when its connected to a P.C)I really have no idea on how to connect microcontroller to hyper terminal?U told that it wud eliminate all issues associated with the converter..right?Plz tell me how to acheive it.Thanks for ur reply...will be waiting for the next one...bye...

 

[VVV]

Re: plz help!

The lines should be high only when idle, which is most of the time, but when there is data there should be pulses going to 0V. You can only see those with a scope, not with a meter.

Connect the MAX232 directly to the PC's serial port. You should then be talikg to the micro directly. Send characters from the keyboard to the uC and see if it responds as it should.

 

[rashmu]

Re: plz help!

Ya thats true...coz we then found that all lines are high there.We checked with CRO.We cud see the pulses for a very short duration...One doubt that has arised is that PC requires the mobile driver to recognize it as modem.Then does a microcontroller too requires it?If so then it requires the driver pgm to be burnt into the controller which is quite cumbersome na..?Wat i thought is that we r just doing serial communication thru MC n thus its not neccesary that it shud recognize mob as modem...Is it ok?Plz clarify this for me.Also told to connect max232 ic to serial port of PC. I dint get how to do it..Can u plz tell me this in detail....?..thanks a lot...

 

[VVV]

Re: plz help!

I did not think it was necessary to recognize the modem. All you should be doing is serial communication

MAX-232 should simply be connected to the PC: TxD to RxD on both ends, that's all. The MAX232 is just the interface between the PC and your MCU.

 

[rashmu]

Re: plz help!

hi....to connect max232 to pc shud we use the rs-232 port given behind the CPU?Also i got to knw abt sumthng called 'sms box' from the net.They say its the device which converts messages from mobile from pdu mode to text mode.Do u hav any idea abt it?Is it available in d market?Since the mobile we r using works only in pdu mode,this device will be very useful for us...Plz tell me if u knw sumthng abt it...thanks a lot..bye