PIC24HJ12GP201 Datasheet, PDF (153/234 Pages) Microchip Technology – High-Performance, 16-Bit Microcontrollers

PIC24HJ12GP201/202
17.0 10-BIT/12-BIT ANALOG-TO-
DIGITAL CONVERTER (ADC)
Note:
This data sheet summarizes the features
of the PIC24HJ12GP201/202 devices. It is
not intended to be a comprehensive
reference source. To complement the
information in this data sheet, refer to the
“PIC24H Family Reference Manual”.
Please see the Microchip web site
(www.microchip.com) for the latest
PIC24H Family Reference Manual
chapters.
The PIC24HJ12GP201/202 devices have up to 10
ADC module input channels.
The AD12B bit (AD1CON1<10>),allows each of the
ADC modules to be configured as either a 10-bit, 4-
sample-and-hold ADC (default configuration) or a 12-
bit, 1-sample-and-hold ADC.
Note: The ADC module must be disabled before
the AD12B bit can be modified.
17.1 Key Features
The 10-bit ADC configuration has the following key
features:
• Successive Approximation (SAR) conversion
• Conversion speeds of up to 1.1 Msps
• Up to 10 analog input pins
• External voltage reference input pins
• Simultaneous sampling of up to four analog input
pins
• Automatic Channel Scan mode
• Selectable conversion trigger source
• Selectable Buffer Fill modes
• Operation during CPU Sleep and Idle modes
• 16-word conversion result buffer
The 12-bit ADC configuration supports all the above
features, except:
• In the 12-bit configuration, conversion speeds of
up to 500 ksps are supported
• There is only 1 sample-and-hold amplifier in the
12-bit configuration, so simultaneous sampling of
multiple channels is not supported.
Depending on the particular device pinout, the ADC
can have up to 10 analog input pins, designated AN0
through AN9. In addition, there are two analog input
pins for external voltage reference connections. These
voltage reference inputs can 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 ADC is shown in Figure 17-1.
17.2 ADC Initialization
To configure the ADC module:
1. Select port pins as analog inputs
(AD1PCFGH<15:0> or AD1PCFGL<15:0>).
2. Select voltage reference source to match
expected range on analog inputs
(AD1CON2<15:13>).
3. Select the analog conversion clock to match
desired data rate with processor clock
(AD1CON3<5:0>).
4. Determine how many sample-and-hold chan-
nels will be used (AD1CON2<9:8> and
AD1PCFGH<15:0> or AD1PCFGL<15:0>).
5. Select the appropriate sample/conversion
sequence
(AD1CON1<7:5>
and
AD1CON3<12:8>).
6. Select the way conversion results are presented
in the buffer (AD1CON1<9:8>).
a) Turn on the ADC module (AD1CON1<15>).
7. Configure ADC interrupt (if required):
a) Clear the AD1IF bit.
b) Select ADC interrupt priority.
© 2007 Microchip Technology Inc.
Preliminary
DS70282B-page 151