>Why do you want to turn off the A/D?  will you not use it again or are
>you trying to save power?

Saving power wouldn't hurt (battery powered robot), but the real reason
for asking is just to write good code and understand the A/D better.

>I've never done it this way.

Ah... that probably means I don't need/want to.  Are you saying you
normally just leave it on (unless it won't be used again for a while)?

- Bri


>> As long as I account for capacitor charge time, can I turn the A/D off
>> and on at will?  Right now I just leave it on...
>>
>> The first line in AD_RA0() leaves the A/D enabled for the life of the
>app.
>> The second line does a delay for A/D capacitor charge time before ADGO.
>> I've placed a comment where I wonder if I could/should turn the A/D off.
>>
>> - Bri
>>
>>
>> void AD_init(void)
>> {
>>   OPTION =3D 0x87;             // Set TMR0 prescaler, and 1:256
>>   ADCON1 =3D 0x02;             // Left justify result, 3 analog channels
>> }
>>
>> unsigned char AD_RA0(void)
>> {
>>   ADCON0 =3D 0x41;             // Fosc/8, A/D enabled
>>   DelayUs(20);               // Allow time for A/D capacitor to charge
>>   ADGO =3D 1;                  // Set the bit to start the conversion
>>   while (ADGO)               // Wait for the conversion to complete
>>     continue;                //
>>   //// could/should disable A/D here?  (w/ADCON0)
>>   return ADRESH;             // Return the AD value (just the top 8=
 bits)
>> }
>
>I see no reason you couldn't turn it off as long as you observer all the
>rules when turning it back on again.  I've never done it this way.  Why do
>you want to turn off the A/D?  will you not use it again or are you trying
>to save power?
>
>
>********************************************************************
>Olin Lathrop, embedded systems consultant in Littleton Massachusetts
>(978) 742-9014, olin@embedinc.com, http://www.embedinc.com
>

9

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