PIC24HJ16GP304-E Datasheet, PDF (157/274 Pages) Microchip Technology – High-Performance, 16-bit Microcontrollers

PIC24HJ32GP202/204 AND PIC24HJ16GP304
18.0 10-BIT/12-BIT
ANALOG-TO-DIGITAL
CONVERTER (ADC)
Note 1: This data sheet summarizes the features
of the PIC24HJ32GP202/204 and
PIC24HJ16GP304 family of devices.
However, it is not intended to be a com-
prehensive reference source. To comple-
ment the information in this data sheet,
refer to “Section 16. Analog-to-Digital
Converter (ADC)” (DS70183) of the
“dsPIC33F/PIC24H Family Reference
Manual”, which is available from the
Microchip website (www.microchip.com).
2: Some registers and associated bits
described in this section may not be
available on all devices. Refer to
Section 4.0 “Memory Organization” in
this data sheet for device-specific register
and bit information.
The PIC24HJ32GP202/204 and PIC24HJ16GP304
devices have up to 13 Analog-to-Digital Conversion
(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.
18.1 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 13 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 13 analog input pins, designated AN0
through AN12. 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 ADC for PIC24HJ16GP304 and
PIC24HJ32GP204 devices is shown in Figure 18-1. A
block diagram of the ADC for the PIC24HJ32GP202
device is shown in Figure 18-2.
18.2 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<7:0>).
4. Determine how many sample-and-hold
channels 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>).
7. Turn on the ADC module (AD1CON1<15>).
8. Configure ADC interrupt (if required):
a) Clear the AD1IF bit.
b) Select ADC interrupt priority.
© 2007-2011 Microchip Technology Inc.
DS70289H-page 157