
2011-2012 Microchip Technology Inc.
Preliminary
DS70657E-page 319
dsPIC33EPXXXGP50X, dsPIC33EPXXXMC20X/50X, AND PIC24EPXXXGP/MC20X
23.0 10-BIT/12-BIT ANALOG-TO-
DIGITAL CONVERTER (ADC)
The dsPIC33EPXXXGP50X, dsPIC33EPXXXMC20X/
50X, and PIC24EPXXXGP/MC20X devices have one
ADC module. The ADC module supports up to 16
analog input channels.
On ADC1, the AD12B bit (AD1CON1<10>) allows each
of the ADC modules to be configured by the user as
either a 10-bit, 4-Sample and Hold (S&H) ADC (default
configuration) or a 12-bit, 1-S&H ADC.
23.1
Key Features
23.1.1
10-BIT ADC CONFIGURATION
The 10-bit ADC configuration has the following key
features:
Successive Approximation (SAR) conversion
Conversion speeds of up to 1.1 Msps
Up to 16 analog input pins
Connections to three internal op amps
Connections to the Charge Time Measurement Unit
(CTMU) and temperature measurement diode
Channel selection and triggering can be con-
trolled by the Peripheral Trigger Generator (PTG)
External voltage reference input pins
Simultaneous sampling of:
- Up to four analog input pins
- Three op amp outputs
- Combinations of analog inputs and op amp
outputs
Automatic Channel Scan mode
Selectable conversion trigger source
Selectable Buffer Fill modes
Four result alignment options (signed/unsigned,
fractional/integer)
Operation during CPU Sleep and Idle modes
23.1.2
12-BIT ADC CONFIGURATION
The 12-bit ADC configuration supports all the features
listed above, with the exception of the following:
In the 12-bit configuration, conversion speeds of
up to 500 ksps are supported
There is only one S&H amplifier in the 12-bit
configuration; therefore, simultaneous sampling
of multiple channels is not supported.
Depending on the particular device pinout, the ADC
can have up to 16 analog input pins, designated AN0
through AN15. These analog inputs are shared with
op amp inputs and outputs, comparator inputs, and
external voltage references. When op amp/comparator
functionality is enabled or an external voltage reference
is used, the analog input that shares that pin is no lon-
ger available. The actual number of analog input pins,
op amps and external voltage reference input
configuration depends on the specific device.
A block diagram of the ADC module is shown in
ADC conversion clock period.
Note 1: This data sheet summarizes the fea-
tures of the dsPIC33EPXXXGP50X,
dsPIC33EPXXXMC20X/50X,
and
PIC24EPXXXGP/MC20X
families
of
devices. It is not intended to be a
comprehensive reference source. To
complement the information in this data
sheet, refer to Section 16. “Analog-to-
Digital Converter (ADC)” (DS70621)
of
the
“dsPIC33E/PIC24E
Family
Reference Manual”, which is availabl
e 2: Some registers and associated bits
described in this section may not be
available on all devices. Refer to
this data sheet for device-specific register
and bit information.
Note:
The ADC module needs to be disabled
before modifying the AD12B bit.