PIC24FJ16MC101_12 Datasheet, PDF (229/350 Pages) Microchip Technology – 16-bit Microcontrollers (up to 32 KB Flash and 2 KB SRAM)

PIC24FJ16MC101/102 AND PIC24FJ32MC101/102/104
22.0 CHARGE TIME
MEASUREMENT UNIT (CTMU)
Note 1: This data sheet summarizes the fea-
tures of the PIC24FJ16MC101/102 and
PIC24FJ32MC101/102/104 family of
devices. It is not intended to be a
comprehensive reference source. To
complement the information in this data
sheet, refer to Section 11. “Charge
Time Measurement Unit (CTMU)”
(DS39724) in the “PIC24F Family
Reference Manual”, which is available
from the Microchip web site
(www.microchip.com).
2: It is important to note that the
specifications in Section 26.0 “Electri-
cal Characteristics” of this data sheet,
supercede any specifications that may be
provided in PIC24F Family Reference
Manual sections.
3: 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 Charge Time Measurement Unit is a flexible ana-
log module that provides accurate differential time
measurement between pulse sources, as well as
asynchronous pulse generation. Its key features
include:
• Four edge input trigger sources
• Polarity control for each edge source
• Control of edge sequence
• Control of response to edges
• Precise time measurement resolution of 1 ns
• Accurate current source suitable for capacitive
measurement
• On-chip temperature measurement using a
built-in diode
Together with other on-chip analog modules, the CTMU
can be used to precisely measure time, measure
capacitance, measure relative changes in capacitance
or generate output pulses that are independent of the
system clock.
The CTMU module is ideal for interfacing with capaci-
tive-based sensors.The CTMU is controlled through
three registers: CTMUCON1, CTMUCON2 and
CTMUICON. CTMUCON1 enables the module, the
Edge delay generation, sequencing of edges and con-
trols the current source and the output trigger.
CTMUCON2 controls the edge source selection, edge
source polarity selection and edge sampling mode. The
CTMUICON register controls the selection and trim of
the current source.
Figure 22-1 shows the CTMU block diagram.
© 2011-2012 Microchip Technology Inc.
Preliminary
DS39997C-page 229