Datasheet
2005-2012 Microchip Technology Inc. DS39747F-page 179
PIC24FJ128GA010 FAMILY
21.0 10-BIT HIGH-SPEED A/D
CONVERTER
The 10-bit A/D Converter has the following key
features:
• Successive Approximation (SAR) conversion
• Conversion speeds of up to 500 ksps
• Up to 16 analog input pins
• External voltage reference input pins
• Automatic Channel Scan mode
• Selectable conversion trigger source
• 16-word conversion result buffer
• Selectable Buffer Fill modes
• Four result alignment options
• Operation during CPU Sleep and Idle modes
Depending on the particular device pinout, the 10-bit
A/D Converter can have up to 16 analog input pins,
designated AN0 through 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. The actual number
of analog input pins and external voltage reference
input configuration will depend on the device. Refer to
the specific device data sheet for further details.
A block diagram of the A/D Converter is shown in
Figure 21-1.
To perform an A/D conversion:
1. Configure the A/D module:
a) Select the port pins as analog inputs
(AD1PCFG<15:0>).
b) Select a voltage reference source to match
the expected range on the analog inputs
(AD1CON2<15:13>).
c) Select the analog conversion clock to match
the desired data rate with the processor clock
(AD1CON3<7:0>).
d) Select the appropriate sample/conver-
sion sequence (AD1CON1<7:0> and
AD1CON3<12:8>).
e) Select how conversion results are
presented in the buffer (AD1CON1<9:8>).
f) Select the interrupt rate (AD1CON2<5:2>).
g) Turn on the A/D module (AD1CON1<15>).
2. Configure the A/D interrupt (if required):
a) Clear the AD1IF bit.
b) Select the A/D interrupt priority.
Note: This data sheet summarizes the features of
this group of PIC24F devices. It is not
intended to be a comprehensive reference
source. Refer to Section 17. “10-Bit A/D
Converter” (DS39705) in the “PIC24F
Family Reference Manual” for more
information.
Note: A/D results should be read with the ADON
bit = 1. If the A/D is disabled before
reading the buffer, it is possible to lose
data.