Datasheet

 2010 Microchip Technology Inc. DS39905E-page 225
PIC24FJ256GA110 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
• 16 Analog Input pins
• External Voltage Reference Input pins
• Internal Band Gap Reference Inputs
• 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
On all PIC24FJ256GA110 family devices, the 10-bit
A/D Converter has 16 analog input pins, designated
AN0 through AN15. In addition, there are two analog
input pins for external voltage reference connections
(V
REF+ and VREF-). These voltage reference inputs
may be shared with other analog input pins.
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) Configure port pins as analog inputs and/or
select band gap reference input
(AD1PCFGL<15:0> and AD1PCFGH<1:0>).
b) Select voltage reference source to match
expected range on 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/conversion
sequence (AD1CON1<7:5> and
AD1CON3<12:8>).
e) Select how conversion results are
presented in the buffer (AD1CON1<9:8>).
f) Select interrupt rate (AD1CON2<5:2>).
g) Turn on A/D module (AD1CON1<15>).
2. Configure the A/D interrupt (if required):
a) Clear the AD1IF bit.
b) Select 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. For more information, refer to the
“PIC24F Family Reference Manual”,
Section 17. “10-Bit A/D Converter”
(DS39705).