i would to create a "DTMF generator application(software)" na illagay ko sa fone ko...anyone knows how to start with it??
;********************************************************************** ;DTMF GENERATION ; by Regulus Berdin ; W holds the key to send ; 10-A 11-B 12-C 13-D 14-* 15-# ; uses 18 cycles per count optimized for 4MHz crystal ; ;DTMF ERROR ;TONE DELAY TONE GENERATED (Hx) % ;697 40 694.4444444 2.56 0.37 ;770 36 771.6049383 1.60 0.21 ;852 33 841.7508418 10.25 1.20 ;941 30 925.9259259 15.07 1.60 ;1209 23 1207.729469 1.27 0.11 ;1336 21 1322.751323 13.25 0.99 ;1477 19 1461.988304 15.01 1.02 ;1633 17 1633.986928 0.99 0.06 cblock LASTVAR lowcnt highcnt slowcnt shighcnt hdcnt ldcnt endc tlowcnt addwf PCL,f dt 30, 40, 40, 40 dt 36, 36, 36, 33 dt 33, 33, 40, 36 dt 33, 30, 30, 30 thighcnt addwf PCL,f dt 21, 23, 21, 19 dt 23, 21, 19, 23 dt 21, 19, 17, 17 dt 17, 17, 23, 19 dtmfsend: andlw 0x0f movwf tmp call tlowcnt movwf slowcnt movwf lowcnt movf tmp,w call thighcnt movwf shighcnt movwf highcnt clrf ldcnt ; movlw .22 ;adjust here for delay movlw MTXLENGTH call EE_read addlw 1 movwf hdcnt ;approx. 100 ms dloop0 clrwdt ;2 nop ; dloop movlw (DHI_PIN + DLOW_PIN) decfsz lowcnt,f andlw DHI_PIN decfsz highcnt,f andlw DLOW_PIN movwf tmp xorwf PORTB,f movf slowcnt,w btfsc tmp,0 movwf lowcnt movf shighcnt,w btfsc tmp,1 movwf highcnt ;13 IF DTMFTESTING nop goto dloop0 ENDIF decfsz ldcnt,f ;2/1 goto dloop0 ;2 decfsz hdcnt,f ;2/1 goto dloop ;2 ;5 return This routine uses 2 pic pins for high and low tones. Just add 2 stage low pass filters the each of the pins and combine both. This works well and has a low error less than dtmf receiver specs.
