ADC Time Question ?

[smiles]

Here is the code that I see from other

[Ttelmah]

You don't.
You need something under 10 _micro_ seconds.
Read the data sheet. The 'key' is that the internal ADC on the PIC, actually starts with a capacitor inside the chip. It is the voltage on this, which is 'read' by the ADC. The capacitor is disconnected from the external world, when the reading is actually 'done'. When you select an ADC channel, it connects the external pin to this capacitor, _which must then be allowed to charge to the voltage before a reading can be done_. The time needed, depends on the size of the capacitor (in the data sheet), the impedance of your source, the internal resistances in the chip, and how close the voltage needs to get. MicroChip recommend a maximum source impedance of 2.5KR (for your particular ADC), and with this, the time needed to get within half a bit value of the actual incoming voltage, is 6.4uSec. Most older chips need a little longer (10uSec typically).
Section 21.1 in the data sheet.
They specify this as:
"After the analog input channel is selected (changed), the channel must be sampled for at least the minimum acquisition time, before starting a conversion".
This is also the time that you must wait _between_ successive readings, since the capacitor is disconnected during a reading.
Some people are rather 'over generous' in the time they allow!...

Best Wishes

[smiles]

That clearly !!!
Thanks so much