Microchip Technology MA330026 Scheda Tecnica

 2011-2014 Microchip Technology Inc.

DS70000652F-page 255

The Charge Time Measurement Unit (CTMU) is a flexible
analog 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 200 ps

• 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
capacitive-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
controls 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.

 shows the CTMU block diagram.

Note 1: This data sheet summarizes the features

of the dsPIC33FJ16(GP/MC)101/102
and dsPIC33FJ32(GP/MC)101/102/104
device families of devices. It is not
intended to be a comprehensive reference
source. To complement the information in
this data sheet, refer to “Charge Time
Measurement Unit (CTMU)” (DS70635)
in the “dsPIC33/PIC24 Family Reference
Manual”, which is available on the
Microchip web site (

www.microchip.com

).

2: Some registers and associated bits

described in this section may not be
available on all devices. Refer to

 in

this data sheet for device-specific register
and bit information.