[plz]8051 + cell phone

wcgan · Nov 1, 2006

sending message from 8051 to cell phone

sorry about that, i dun know where should i post this topic..
i just wan do a simple thing ..
connect cell phone with microcontroller 8051 to send a msg ...
how can i connect it?
can... anyone answer me?
thanks a lot.

budhy · Nov 1, 2006

i just wan do a simple thing ..
connect cell phone with microcontroller 8051 to send a msg ...

It is not a simple thing at all!

First connect you cell phone to 8051 TxD and RxD pin, you need some resistor to translate logic Voltage level between them (8051 run on 5V, Cell Phone 3.3V). The definite circuit depend on what kind of cell phone you use.

Then you have to study AT Command to communicate with Cell Phone to send message.

Please mention your cell phone, I'll give you further information.

wcgan · Nov 2, 2006

thanks a lot ..
i am using nokia 8250...
i dun know how connect 8250 to 8051?
is tat nokia 8250 have serial cable?
i know some AT commands already..
actually, my project have 2 part, i done the software part ....
which is use vb to received msg...
just dun know how use microcontroller to send msg..
can u give me some info? thanks a lot..

budhy · Nov 2, 2006

The pin out of Nokia 8250 : https://pinouts.ru/CellularPhones-Nokia/nokia_8210_pinout.shtml
and the connection diagram between 8051 and Nokia 8250 shown below:

Next step you have to read 8051 datasheet, learn how to :
1. configure 8051's UART working at 9600 Baud with 8 data bit, no parity bit, 1 stop bit data format
2. write a SerialOutput routine to send AT command to Nokia 8250
3. write a SerialInput routine to receive Nokia 8250 status

You can do it with assembly language or C language.

Good luck

wcgan · Nov 3, 2006

thanks a lot...
i will try it ...
thanks .... really very thanks..

Lru · Nov 7, 2006

When i am doing the assembly of 8051, how I transfer the AT command to the cell phone and am I need to convert these commands to PDU code first?

Hero · Nov 7, 2006

Hi,

You need ASCII AT commands in PDU mode. Look at appropriate GSM standards and mobile manuals how to use AT commands in PDU mode.

budhy · Nov 8, 2006

Lru wrote:

When i am doing the assembly of 8051, how I transfer the AT command to the cell phone

Here is the way use 8051 to sent AT Command to the cell phone:

Code:

Main:
     MOV   R0,#CMGF
     ACALL StringOut   ; sent AT+CMGF? to cell phone
     .....
;
CMGF:
     DB    'AT+CMGF?',0x0D,0x0A,0x00
;
; Character Output to Serial port
;
CharOut:
     JNB   TI,CharOut
     CLR   TI
     MOV   SBUF,A
;
; String Output to Serial port
;
StringOut:
     MOV   A,@R0
     INC   R0
     JNZ   CharOut
     RET

am I need to convert these commands to PDU code first?

There are two kind of Cell phone, the first one is send/receive SMS message in PDU mode only, the other one is send/receive SMS message in PDU mode or TEXT mode.

Above example perform checking cell phone message format, if answer is
+CMGF=1
or
+CMGF=(0,1)
it mean your cell phone support TEXT format SMS, you don't need to convert message to PDU

if answer is
+CMGF=0
you have to convert message to PDU

Lru · Nov 8, 2006

Thank you very much, but there got something i don`t understand.

CMGF:
DB 'AT+CMGF?',0x0D,0x0A,0x00

So that I need to convert the 'AT+CMGF?' into ascii code first then just key in is it?

CharOut:
JNB TI,CharOut
CLR TI
MOV SBUF,A

In these four lines, is that SBUF and TI is a register in 8051 for serial port?

Sorry for trouble you and thank you very much.

budhy · Nov 9, 2006

So that I need to convert the 'AT+CMGF?' into ascii code first then just key in is it?

The statement is to create an ASCII string, which in turn to be transmitt via serial port.

In these four lines, is that SBUF and TI is a register in 8051 for serial port?

Those four line is Serial Output routine for 8051.

wcgan · Nov 11, 2006

budhy said:
and the connection diagram between 8051 and Nokia 8250 shown below:

need change voltage or not?
can direct connect 8051's TX,RX to 8250's TX,RX ?
or need use RS232 or MAX232 to change the voltage?

budhy · Nov 11, 2006

need change voltage or not?

Need change voltage, but already done on the circuit

can direct connect 8051's TX,RX to 8250's TX,RX ?

8051's RX can direct connect to 8250's TX
8051's TX can't direct connect to 8250's RX, use MC14050 (operate on 3.3 V) as voltage translator

need use RS232 or MAX232 to change the voltage?

No!

wcgan · Nov 11, 2006

8051's TX can't direct connect to 8250's RX, use MC14050 (operate on 3.3 V) as voltage translator

i am found the datasheet is this..
connect like this?

must use this IC to change voltage? can i use diode change the voltage of 8051's 5v to 3v?

budhy · Nov 11, 2006

Yes, the complete connection like that.

must use this IC to change voltage? can i use diode change the voltage of 8051's 5v to 3v?

As I mention before, you can use resistor voltage divider for voltage translator, like this:

wcgan · Dec 10, 2006

budhy said:
As I mention before, you can use resistor voltage divider for voltage translator, like this:

sorry..
i got another question, how can i connect the power supply into cell phone?
A B C D
A = 3.6v
D = 0v
i connected to power supply, but my cell phone cannot ON..
how can i connect it?
thx..

budhy · Dec 10, 2006

A B C D
A = 3.6v
D = 0v

I don't mention that, and I have no power connector information.

wcgan · Dec 10, 2006

budhy said:
A B C D
A = 3.6v
D = 0v

Click to expand...

I don't mention that, and I have no power connector information.

nvm.... anywhere.. thanks a lot...
after i know tat information, i will post at here..
thx

omidgold · Dec 10, 2006

it is depend on your cell phone

wcgan · Dec 13, 2006

omidgold said:
it is depend on your cell phone

my cell phone is 8250...
i just connect the A B C D to a cable and then connect to battery...
just let my cell phone switch ON

budhy · Dec 13, 2006

I don't have information of internal power connector on 8210, but I am sure you can connect power to external connector

[plz]8051 + cell phone

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