Datasheet

© 2009-2011 Microchip Technology Inc. DS61156G-page 153
PIC32MX5XX/6XX/7XX
22.0 10-BIT ANALOG-TO-DIGITAL
CONVERTER (ADC)
The PIC32MX5XX/6XX/7XX 10-bit Analog-to-Digital
Converter (ADC) includes the following features:
• Successive Approximation Register (SAR)
conversion
• Up to 1 Msps conversion speed
• Up to 16 analog input pins
• External voltage reference input pins
• One unipolar, differential Sample and Hold
Amplifier (SHA)
• Automatic Channel Scan mode
• Selectable conversion trigger source
• 16-word conversion result buffer
• Selectable buffer fill modes
• Eight conversion result format options
• Operation during CPU Sleep and Idle modes
A block diagram of the 10-bit ADC is illustrated in
Figure 22-1. The 10-bit ADC has up to 16 analog input
pins, designated AN0-AN15. In addition, there are two
analog input pins for external voltage reference
connections. These voltage reference inputs may be
shared with other analog input pins and may be
common to other analog module references.
The analog inputs are connected through two multi-
plexers (MUXs) to one SHA. The analog input MUXs
can be switched between two sets of analog inputs
between conversions. Unipolar differential conversions
are possible on all channels, other than the pin used as
the reference, using a reference input pin (see
Figure 22-1).
The Analog Input Scan mode sequentially converts
user-specified channels. A control register specifies
which analog input channels will be included in the
scanning sequence.
The 10-bit ADC is connected to a 16-word result buffer.
Each 10-bit result is converted to one of eight 32-bit
output formats when it is read from the result buffer.
FIGURE 22-1: ADC1 MODULE BLOCK DIAGRAM
Note 1: This data sheet summarizes the features
of the PIC32MX5XX/6XX/7XX family of
devices. It is not intended to be a
comprehensive reference source. To
complement the information in this data
sheet, refer to
Section 17. “10-bit
Analog-to-Digital Converter (ADC)”
(DS61104) in the “PIC32 Family
Reference Manual”, which is available
from the Microchip web site
(www.microchip.com/PIC32).
2: Some registers and associated bits
described in this section may not be
available on all devices. Refer to
Section 4.0 “Memory Organization” in
this data sheet for device-specific register
and bit information.
SAR ADC
S/H
ADC1BUF0
ADC1BUF1
ADC1BUF2
ADC1BUFF
ADC1BUFE
AN0
AN15
AN1
VREFL
CH0SB<4:0>
CH0NA CH0NB
+
-
CH0SA<4:0>
Channel
Scan
CSCNA
Alternate
V
REF+
(1)
AVDD AVSS
VREF-
(1)
Note 1: VREF+ and VREF- inputs can be multiplexed with other analog inputs.
Input Selection
V
REFH
VREFL
VCFG<2:0>