PIC12F1822 MICROCHIP [Microchip Technology], PIC12F1822 Datasheet - Page 134

• Manufacturer Part Number: PIC12F1822
• Description: 8/14-Pin Flash Microcontrollers with nanoWatt XLP Technology
• Manufacturer: MICROCHIP [Microchip Technology]

PIC12F/LF1822/16F/LF1823
15.1
When configuring and using the ADC the following
functions must be considered:
• Port configuration
• Channel selection
• ADC voltage reference selection
• ADC conversion clock source
• Interrupt control
• Result formatting
15.1.1
The ADC can be used to convert both analog and
digital signals. When converting analog signals, the I/O
pin should be configured for analog by setting the
associated
Section 12.0 “I/O Ports” for more information.
15.1.2
There are up to 10 channel selections available:
• AN<3:0> pins (PIC12F/LF1822 only)
• AN<7:0> pins (PIC16F/LF1823 only)
• DAC Output
• FVR (Fixed Voltage Reference) Output
Refer to Section 16.0 “Digital-to-Analog Converter
(DAC) Module” and Section 14.0 “Fixed Voltage
Reference (FVR)” for more information on these chan-
nel selections.
The CHS bits of the ADCON0 register determine which
channel is connected to the sample and hold circuit.
When changing channels, a delay is required before
starting the next conversion. Refer to Section 15.2
“ADC Operation” for more information.
15.1.3
The ADPREF bits of the ADCON1 register provides
control of the positive voltage reference. The positive
voltage reference can be:
• V
• V
• FVR
See Section 14.0 “Fixed Voltage Reference (FVR)”
for more details on the fixed voltage reference.
DS41413A-page 134
Note:
REF
DD
+ pin
ADC Configuration
PORT CONFIGURATION
Analog voltages on any pin that is defined
as a digital input may cause the input buf-
fer to conduct excess current.
CHANNEL SELECTION
ADC V
TRIS
OLTAGE REFERENCE
and
ANSEL
bits.
Refer
Preliminary
to
15.1.4
The source of the conversion clock is software select-
able via the ADCS bits of the ADCON1 register. There
are seven possible clock options:
• F
• F
• F
• F
• F
• F
• F
The time to complete one bit conversion is defined as
T
ods as shown in Figure 15-2.
For correct conversion, the appropriate T
tion must be met. Refer to the A/D conversion require-
ments in Section 29.0 “Electrical Specifications” for
more information. Table 15-1 gives examples of appro-
priate ADC clock selections.
AD
Note:
OSC
OSC
OSC
OSC
OSC
OSC
RC
. One full 10-bit conversion requires 11.5 T
(dedicated internal oscillator)
/2
/4
/8
/16
/32
/64
Unless using the F
system clock frequency will change the
ADC
adversely affect the ADC result.
CONVERSION CLOCK
clock
 2010 Microchip Technology Inc.
frequency,
RC
, any changes in the
which
AD
specifica-
AD
may
peri-