Отправлено иа 09 ноября 2003 г. 17:36 В ответ на: Вопрос по калибровке PIC16F630 отправлено Aleks_ 09 ноября 2003 г. 16:20

The bandgap reference circuit is used to generate a 1.2V nominal stable voltage reference for the A/D and the low-voltage detector. The bandgap reference is channel 4 of the analog mux. The bandgap reference voltage is stored in the calibration space EPROM (See Table 4-2). To enable the bandgap reference REFOFF (SLPCON<5>) must be cleared.

Periodic conversion cycles should be performed on the bandgap and slope references (described in Section 9.0) to compensate for A/D component drift.
Measurements for the reference voltage count are equated to the voltage value stored into EPROM during calibration. All other channel measurements are compensated for by ratioing the actual count with the
bandgap count and multiplying by the bandgap voltage value stored in EPROM. Since all measurements are relative to the reference, offset voltages inherent in the comparator are cancelled out. See AN624, “PIC14000 A/D Theory and Implementation” for further details of
A/D operation.

Bandgap Reference Controlled by REFOFF, SLPCON<5>
B5 REFOFF
References Power Control (bandgap reference, low voltage detector, bias generator)
1 = The references are off
0 = The references are on