gsm modem with 16f877a

[Ioannis]

Modem PIC
Tx -----------X-----------------Rx
Rx ------X----|-----------------Tx
| |
1k 1k
| |
PC |----|
Rx-------X---X

Hope this helps you understand.

Ioannis

[kumara]

Mr Ioannis now i can send sms (i have 1 mistake rx and tx chang)but now i want to do read sms and high led.please help methank you

[Ioannis]

This example subroutine is for Wavecom. You have to check the manual of your GSM device for the correct commands.
Also this example supposes that the GSM device responds with ASCII characters and not with numbers. OK instead of 0 (zero).

GSM_Subroutine:
HSerout ["AT+CMGL=",34,"ALL",34,13] 'Check if there is new SMS. 34 is for " symbol
Hserin 5000,err,[wait(10,13,10),str command\2]
if command[0]="O" then return	'If response was just OK, then there was no SMS
if command[0]="+" then goto read_sms 'If response started with + sign then there was some sms

err:
return

read_sms:
Lcdout com,line1,"Reading SMS",rep " "\4
for l=0 to 5:command[l]=0:next l    'Clear buffer
GoSub Mobile_Number      'get mobile number from setup, to check correct admin number
HSerout ["AT+CMGL=",34,"ALL",34,13]  '"ALL" is for Wavecom module. Read all SMS 
' Read Caller ID etc. The timeout value in the HSERIN statement is important.
' it takes some time before the phone replies to the AT+CMGL command
HSerin 5000,ex_sms4,[wait("READ"),skip 4,waitstr command\10,skip 27,STR command\6\13] 'Number is waitstr command\10
LCDOut com,line1,"Read 1 SMS",rep " "\4,com,line2,"Command: ",str command\6

sms_delete:
HSerout ["AT+CMGD=1,4",13]			'Delete all messages
LCDOut com,line1,"Deleting SMS":pause 150
HSerin 15000,ex_sms2,[wait("OK")]     'Wait for OK (null)
LCDOut com,line1,"Deleted SMS ":Pause 1000
GoTo lcd_cls

ex_sms2:    'No new message or timeout error
LCDOut com,line2,"Error",rep " "\11:Pause 1000
GoTo sms_chk

ex_sms3:
LCDOut com,line2,"SMS Check Error":Pause 1000
GoTo sms_delete

ex_sms4:    'Wrong Number!
LCDOut com,line2,"Error phone Nbr":Pause 1000
GoTo sms_delete

I repeat again, study your GSM AT commands before attempting anything.
Ioannis

[kumara]

Mr.Ioannis

I HAVE FIND SOME CODE ABOUT AND I WROTE SOME CODE "AT+CMGD"
I SEND TO MODEM TO SMS "A" BUT NOT TURN ON PORTB.6

WHAT'S THE WRONG THIS CODE HELP ME
' Def
define OSC 4
DEFINE HSER_SPBRG 25
DEFINE HSER_TXSTA 20h
DEFINE HSER_RCSTA 90h
DEFINE HSER_BAUD 2400
DEFINE HSER_CLROERR 1

sms VAR BYTE[16]

I VAR BYTE

'Check sms

begin:
HIGH PORTB.7
HSerout ["AT",13,10]' start comm
HSERIN 2000,begin,[WAIT("OK")]
LOW PORTB.7


query:
HSEROUT["AT+CMGL=",34,"REC READ",34,13,10]' filter for query
HSERIN 5000,query,[WAIT("REC READ"),skip 41, STR sms\16\13]
HIGH PORTB.5
PAUSE 200
LOW PORTB.5
I=0

WHILE I <> 13' count until 13
if sms[i]=$44 THEN ' searching for letter A ?
GOTO turnon:
ELSE
GOTO back
I=I+1
ENDIF
WEND
turnon:
High PortB.6
pause 1000
HSerout ["AT+CMGD=1",13,10]
low portb.6
GOTO QUERY
back:
HIGH PORTB.4
HSerout ["AT+CMGD=1",13,10]
PAUSE 100
LOW PORTB.4
GOTO QUERY
END

xxxxx.

[Ioannis]

Are you sure the x y z modem that you have not study yet, is working at 2400 ?

I am sorry but cannot guess. Nor I have the magic ball to tell me what you have, how it must be set-up. It is your job to do it.

Ioannis

[starwick]

Hi,
First make sure you connect the pic rx and tx trough 10k resitor to the modem's rx and tx pin, Then you need to tie the handhaking pins together on the modem side.
Start with pin 7 and 8 tied together and see if u get some data if not then tie pins 4 AND 6.Most modems required handshaking by tieing these pins the modem will be always ready to send and receive other wise it will sit and wait. Good luck hope this will help.

[kumara]

my sms project

3 input and 3 out put