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i am a noob and learning 8051 coding. i want to know how can i use PWM to write a speaker which can emit diff sound (do,re,mi,etc.) by using 2 pins only. thanks.
HI.
i no people will complain bout my style but here is code with my comments
;=================================================== ; ; Name : DoNote ; ; Purpose : Produce a sound on P1.0 ; ; Parameters : int Cycles (R6:R7) ; unsigned char Delay (R5) ; ; Result : void ; ;=================================================== ?PR?DoNote?sound segment code rseg ?PR?DoNote?sound DoNote: clr a ; Get 0-'Cycles' clr c ; Bcoz code uses up counter subb a,r7 ; And store to dptr mov dpl,a clr a subb a,r6 mov dph,a mov dpl,a Dn_1: cpl p1.0 ; Toggle the port pin mov a,r5 ; Get 'Delay' mov r2,a ; Loop for 'Delay' djnz R2,$ inc dptr ; Update cycle counter mov a,dpl ; While count is not overflowed or a,dph jnz Dn_1 ; Loop ret
in yo're c do this
extern void DoNote ( int Cycles, char delay ); void DoNote ( void ) { DoNote ( }
so there is a donation more than others.
Always yo're freind.
Zeusti.
two many things to do here!
extern void DoNote ( int Cycles, char delay ); void foo ( void ) { DoNote ( 10000, 10 ); }
Zeusti,
I'll make no comments about your comments, but I noticed a little error in your code:
;=================================================== ; ; Name : DoNote ; ; Purpose : Produce a sound on P1.0 ; ; Parameters : int Cycles (R6:R7) ; unsigned char Delay (R5) ; ; Result : void ; ;=================================================== ?PR?DoNote?sound segment code rseg ?PR?DoNote?sound DoNote: clr a ; Get 0-'Cycles' clr c ; Bcoz code uses up counter subb a,r7 ; And store to dptr mov dpl,a clr a subb a,r6 mov dph,a ; mov dpl,a <<< I think this should not be here Dn_1: cpl p1.0 ; Toggle the port pin mov a,r5 ; Get 'Delay' mov r2,a ; Loop for 'Delay' djnz R2,$ inc dptr ; Update cycle counter mov a,dpl ; While count is not overflowed or a,dph jnz Dn_1 ; Loop ret
you are write. sorry.
so so many things to do here!
thanks all very much. i can now handle the software part of my purpose, but for the hardware, i've got some difficulty. i dont know how to amplify the sound of the 8ohm speaker. should i use any op-amp? or it can be done by varying the voltage?
This has nothing to do with the 8051 or Keil tools.
You need some books on basic electronics!
eg, www.kpsec.freeuk.com/trancirc.htm
the page from master neil is good.
look at the para "Choosing a suitable NPN transistor"
u can simly have the speeker for the load.