Re: [Sdcc-user] Setting up and sending serial messages

[Gernot F. <g....@gm...>]

On Mon, 20 Jun 2005, you wrote:
> Hi Peter,
>=20
> --- Peter <pl...@ac...> wrote:
> >
> >=20
> > NOT TANGO ONER, TANGO INDIA. You made a typo. Sigh.
> >=20
>=20
> Yup, I did.  Sorry about that.  Next time I'll
> definitely double check :-)
>=20
> Also, I have another quick question.  How would you
> write the code if you didn't want to use the standard
> serial TXD pin on the 2051 and were to use a general
> I/O pin like P1.7?  This would free up the built in
> serial pins so I can use them for communicating with a
> PC.

this works with software-serial in an interrupt.
The interrupt must run 5 times the baudrate.
p1.2 and p1.3 are used.

void sendch(char c)
{
=09while(sec!=3D0);
=09sed=3Dc;
=09sec=3D10;
}
char getch()
{
=09while(byteready=3D=3D0);
=09byteready=3D0;
=09return recbuf;
}
void timer0int(void) interrupt 1
{          =20
  =20
        _asm
        djnz  _timer0int_sendps_1_1,00005$
        mov a,_sec
        jz 00001$
        cjne a,#10,00002$
        clr _P1_3
        sjmp 00003$
        00002$: ;c is set from cjne !
        mov a,_sed
        rrc a
        mov _P1_3,c
        mov _sed,a
        00003$: dec _sec
        00001$:
        mov  _timer0int_sendps_1_1,#5
        00005$:

        djnz _timer0int_recps_1_1,00011$
        inc _timer0int_recps_1_1
        jb _reciving,00010$
        jb _P1_2,00011$
        setb _reciving
        mov  _timer0int_recpu_1_1,#255
        mov  _timer0int_recps_1_1,#3
        sjmp 00011$
        00010$:
        mov _timer0int_recps_1_1,#5
        mov c,_P1_2
        mov a,_timer0int_recpu_1_1
        rrc a
        mov _timer0int_recpu_1_1,a
        jc 00011$
        setb _byteready
        mov _recbuf,a
        clr _reciving
        00011$:  =20
        _endasm=09 =20
        =20
}

>=20
> Thanks again and sorry about the really n00bish
> mistake :-)
>=20
> J Silverman
>=20
>=20
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--=20
MFG Gernot