Datasheet

© 2011-2012 Microchip Technology Inc. Preliminary DS39997C-page 195
PIC24FJ16MC101/102 AND PIC24FJ32MC101/102/104
FIGURE 19-4: ADC CONVERSION CLOCK PERIOD BLOCK DIAGRAM
19.3 ADC Helpful Tips
1. The SMPI<3:0> (AD1CON2<5:2>) control bits:
a) Determine when the ADC interrupt flag is
set and an interrupt is generated if enabled.
b) When the CSCNA bit (AD1CON2<10>) is
set to ‘1’, determines when the ADC analog
scan channel list defined in the AD1CSSL
register starts over from the beginning.
2. The ADC has 16 result buffers. ADC conversion
results are stored sequentially in ADC1BUF0-
ADC1BUFF regardless of which analog inputs
are being used subject to the SMPI<3:0> bits
(AD1CON2<5:2>). There is no relationship
between the ANx input being measured and
which ADC buffer (ADC1BUF0-ADC1BUFF)
that the conversion results will be placed in.
3. The DONE bit (AD1CON1<0>) is only cleared
at the start of each conversion and is set at
the completion of the conversion, but remains
set indefinitely even through the next sample
phase until the next conversion begins. If
application code is monitoring the DONE bit in
any kind of software loop, the user must con-
sider this behavior because the CPU code
execution is faster than the ADC. As a result,
in manual sample mode, particularly where
the users code is setting the SAMP bit
(AD1CON1<1>), the DONE bit should also be
cleared by the user application just before set-
ting the SAMP bit.
19.4 ADC Resources
Many useful resources are provided on the main prod-
uct page of the Microchip web site for the devices listed
in this data sheet. This product page, which can be
accessed using this link, contains the latest updates
and additional information.
19.4.1 KEY RESOURCES
• Section 46. “10-bit Analog-to-Digital Converter
(ADC) with 4 Simultaneous Conversions”
(DS39737)
• Code Samples
• Application Notes
• Software Libraries
• Webinars
• All related PIC24F Family Reference Manual
sections
• Development Tools
1
0
ADC Internal
RC Clock
(1)
T
OSC
(1)
X2
ADC Conversion
Clock Multiplier
1, 2, 3, 4, 5,..., 64
ADxCON3<15>
TCY
TAD
6
ADxCON3<5:0>
Note 1: See the ADC specifications in Section 26.0 “Electrical Characteristics” for the exact RC clock value.
Note: In the event you are not able to access
the product page using the link above,
enter this URL in your browser:
http://www.microchip.com/wwwproducts/
Devices.aspx?dDocName=en554339