
2005 Microchip Technology Inc.
Preliminary
DS41265A-page 149
PIC16F946
12.0
ANALOG-TO-DIGITAL
CONVERTER (A/D) MODULE
The Analog-to-Digital converter (A/D) allows conversion
of an analog input signal to a 10-bit binary representation
of that signal. The PIC16F946 has up to eight analog
inputs, multiplexed into one sample and hold circuit. The
output of the sample and hold is connected to the input of
the converter. The converter generates a binary result via
successive approximation and stores the result in a 10-bit
register. The voltage reference used in the conversion is
software selectable to either VDD or a voltage applied by
the VREF pin. Figure 12-1 shows the block diagram of the A/D on the PIC16F946.
FIGURE 12-1:
A/D BLOCK DIAGRAM
RA0/AN0/C1-/SEG12
A/D
RA1/AN1/C2-/SEG7
RA2/AN2/C2+/VREF-/COM2
RA5/AN4/C2OUT/SS/SEG5
VDD
VREF+
ADON
GO/DONE
VCFG0 = 1
VCFG0 = 0
CHS<2:0>
ADRESH ADRESL
10
ADFM
VSS
RE0/AN5/SEG21
RE1/AN6/SEG22
RE2/AN7/SEG23
RA3/AN3/C1+/VREF+/SEG15
VCFG1 = 1
VCFG1 = 0
VREF-