PIC24FJ128GA Datasheet, PDF (167/232 Pages) Microchip Technology – General Purpose, 16-Bit Flash Microcontrollers

PIC24FJ128GA FAMILY
20.0 10-BIT HIGH-SPEED A/D
CONVERTER
Note:
This data sheet summarizes the features
of this group of PIC24FJ devices. It is not
intended to be a comprehensive reference
source.
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, des-
ignated AN0 through AN15. In addition, there are two
analog input pins for external voltage reference con-
nections. 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 specific device.
Refer to the device data sheet for further details.
A block diagram of the A/D converter is shown in
Figure 20-1.
To perform an A/D conversion:
1. Configure the A/D module:
a) Select port pins as analog inputs
(AD1PCFG<15:0>).
b) Select voltage reference source to match
expected range on analog inputs
(AD1CON2<15:13>).
c) Select the analog conversion clock to
match desired data rate with processor
clock (AD1CON3<7:0>).
d) Select the appropriate sample/conversion
sequence (AD1CON1<7:0> 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 A/D interrupt (if required):
a) Clear the AD1IF bit.
b) Select A/D interrupt priority.
© 2006 Microchip Technology Inc.
Preliminary
DS39747C-page 165