You do not wait 10us, Shawn...

Tamas


On 18/09/06, Shawn Wilton <black9@gmail.com> wrote:
>
> I'll give that a shot Vasile, but it looks like what I'm already doing.
>
>
> On 9/18/06, Vasile Surducan <piclist9@gmail.com> wrote:
> >
> > This is a jal procedure for reading the AD module of the 12F675. I
> > think is self explanatory. Try to convert it in C and will (probably)
> > work.
> >
> > const bit ref_extern    = high
> > const bit ref_vdd       = low
> > const bit left_justify  = high
> > const bit right_justify = low
> >
> > procedure one_ch_ad_read ( byte in channel, bit in ref, bit in justify )
> > is
> > ; result in adresh and adresl,
> > ; channel = 0...3, ref=high means external reference, justify=high
> > means left justify
> >    var byte local
> >    if    channel == 0 then local = 0b_0000_0001
> >    elsif channel == 1 then local = 0b_0000_0010
> >    elsif channel == 2 then local = 0b_0000_0100
> >    elsif channel == 3 then local = 0b_0000_1000
> >    end if
> >    asm bsf _rp0    ; set bank1
> >    ansel = ( 0b_0001_0000 + local ) ; fosc/8, internal 4MHz clock
> >    asm bcf _rp0    ; set bank0
> >    channel = channel << 2
> >    adcon0 = ( 0 + channel )
> >   if ref then
> >      asm bsf vcfg
> >   else asm bcf vcfg
> >   end if
> >   if justify then
> >       asm bcf adfm
> >   else asm bsf adfm
> >   end if
> >
> >    asm bsf adon                    ; supply the ad module
> >    delay_10uS ( 1 )                ; wait the sampling time
> >    asm bsf go_done                 ; start the conversion
> >    while go_done loop end loop     ; wait for ad completion
> > end procedure
> >
> > usage:
> > one_ch_ad_read ( 0, ref_vdd, left_justify )
> > read the adresh and adresl
> >
> >
> > On 9/18/06, Shawn Wilton <black9@gmail.com> wrote:
> > > Yeah, I have tried this and the conversion never returns.  I block on
> > the
> > > poll of the Go\Not Done bit and it never changes back to a zero
> > indicating a
> > > successful conversion.
> > >
> > >
> > > On 9/18/06, Vasile Surducan <piclist9@gmail.com> wrote:
> > > >
> > > > There are two wais (at least) of using the AD module in PIC
> > > > microcontrollers.
> > > > First one is: set the AD channels and device operating frequency,
> turn
> > > > on the AD module, wait 20uS for aquisition time and wait untill the
> > > > GO/DONE bit is changing
> > > --
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> > >
> > --
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> >
>
>
>
> --
>
> Shawn Wilton (b9 Systems)
> http://b9Systems.com  <- New web page
> --
> http://www.piclist.com PIC/SX FAQ & list archive
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> http://mailman.mit.edu/mailman/listinfo/piclist
>



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