another benq m23 problem

[m0nm0n]

dun po sa module, kapag nakakabit na ung tx pin ng benqm23 gsm module sa rx pin ng pic16f877a, hindi po xa nagsesend ng message pero kapag nakatanggal naman, eh ok naman xa, nag tetext naman, what could be the problem po? T_T

this is our connection:
Benqm23 gsm module   <------>    PIC16F877A

        tx                     <----->           rx
        rx                     <----->           tx   
        gnd                   <----->          gnd

Important Note:

It is possible to not use limiting resistors between the tx pin of the pic16f877a and the GSM module because we had tested the output voltage of the tx of pic16f877a and it is 3.3v... n_n.. nagkaproblema kc kami nun at sinunod namin ung sa module ng benqm23 without even testing the voltage output. kaya aun,. ndi naman sa cnsbe ko mali ung sa benqm23 na instructions pero mali lng tlga. haha.cguro depende na din sa supply???

slamat po s magrereply. hehe

[marcelino]

Important Note:

It is possible to not use limiting resistors between the tx pin of the pic16f877a and the GSM module because we had tested the output voltage of the tx of pic16f877a and it is 3.3v... n_n.. nagkaproblema kc kami nun at sinunod namin ung sa module ng benqm23 without even testing the voltage output. kaya aun,. ndi naman sa cnsbe ko mali ung sa benqm23 na instructions pero mali lng tlga. haha.cguro depende na din sa supply???

slamat po s magrereply. hehe

how can that be???
is your power supply for PIC is 3.3V?

[m0nm0n]

e2 nga po pla ung prgram namin.


DEFINE HSER_CLOERR 1


ledok var PORTB.6
B1      var     byte
char var byte
buff var byte[2]
ABC var byte[10]


' Initialize USART
      DEFINE HSER_TXSTA 24h
      DEFINE HSER_RCSTA 90h
      DEFINE HSER_BAUD 9600
        TRISC = %10111111       ' Set TX (PortC.6) to out, rest in
      TRISB = %00000000
       

'----------------------
led:
   ledok = 1
   
   if ledok = 1 Then

   gosub start
   goto getreplyAT
   endif
    goto led
start: 
   RCSTA.4 = 0
   Hserout[13,10]
   pause 500

   Hserout ["AT", 13,10]   ' Send text followed by carriage return and linefeed
   pause 500
   
   Hserout ["AT", 13,10]   ' Send text followed by carriage return and linefeed
   pause 500
   RCSTA.4 = 1
   return
getreplyAT:
   Hserin [STR ABC\2]
   if ABC(0) = "O" then
      if ABC(1)="K"   then
         gosub sendsms
      endif
   pause 500
         endif
   goto start


sendsms:   
      Hserout["AT+CMGF=1",13,10]
      pause 1000
      Hserout["AT+CMGS=",34,"09277940442",34,13,10]
      pause 1000
      Hserout["GSM READY!",13,10]
      Hserout[26]
      pause 1000
       return



   End

[m0nm0n]

un nga din po nakaktaka dun eh. ung supply namin is 5v.. aun. tpos nung tinest namin output ng tx pin, nsa 3.3 tlga xa. hehe. try it!! n_n

[marcelino]

un nga din po nakaktaka dun eh. ung supply namin is 5v.. aun. tpos nung tinest namin output ng tx pin, nsa 3.3 tlga xa. hehe. try it!! n_n

tangalin mo yung modem, measure mo nga ang voltage output sa tx ng PIC.

you must consider the design guide sa manual:
http://www.e-gizmo.com/KIT/images/gsm/GSM%20Modem%20Rev%201r0.pdf
on page 7

[m0nm0n]

inulit po namin ang testing at nasa 3.3v talaga ung output voltage nya..gamit namin power supply is ung power supply ng mga desktop computers. hehe. tpos try din namin gamitin ung adaptor n ksma sa gsm module. aun. ang prob po talaga is kapag nakakabit ung rx ng pic and tx ng gsm, ndi nag tetext ung gsm. wla nmn po problem sa sending kc nag sesend nmn po xa kapag nakakabit ung tx ng pic sa rx ng gsm module. aun. anu kea prob. T_T