DM240313 Microchip Technology, DM240313 Datasheet - Page 27

• Manufacturer Part Number: DM240313
• Description: BOARD DEMO 8BIT XLP
• Manufacturer: Microchip Technology
• Series: XLP™r
• Type: MCUr

Specifications of DM240313

• Contents: Board
• Data Bus Width: 8 bit
• Silicon Manufacturer: Microchip
• Core Architecture: PIC
• Core Sub-architecture: PIC16, PIC18
• Silicon Core Number: PIC16F, PIC18F
• Kit Contents: Board
• Features: 32 Character Backlit LCD Display, Temperature Sensor
• Rohs Compliant: Yes
• Silicon Family Name: PIC18FxxKxx
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

3.3
 2011 Microchip Technology Inc.
CURRENT MEASUREMENT
3.2.15
The PICkit header (J3) can be used by either the PICkit™ 2 or PICkit™ 3 programming
devices. Through use of the PICkit 3 the user is capable of debugging the included
demonstration software or creating and debugging custom software in use with the
8-bit XLP.
An advantage to the XLP 8-bit board is its provisions for in-circuit current measurement.
Using simple techniques and equipment, users can experiment directly with low-power
hardware and software techniques, then directly measure their current consumption
without introducing measurement induced artifacts. This provides a fast method of
directly validating power-saving strategies. To make measurements more useful, the
development board allows for the measurement of microcontroller current draw and
non-microcontroller component current separately.
3.3.1
To measure current consumed by the PIC microcontrollers, the VMCU jumper (J15)
can be removed and a current measurement cable connected to its pins. This allows
the user to empirically evaluate the microcontroller’s various low-power features. Since
J15 interrupts the microcontroller’s V
when measurements are not being taken. To avoid starving the microcontroller’s cur-
rent supply and causing low-power conditions, it may be necessary to switch the
ammeter to a higher current range during programming and full-power operation. When
the microcontroller is operating in a low-power state, switching to a low range will pro-
duce a more accurate measurement.
3.3.2
The VBOARD jumper (J16) allows the user to measure the current consumed by the
various board components. It also permits the user to experiment with low-power tech-
niques on a variety of commonly used components. Current measurements taken at
J16 exclude current consumption from the microcontroller, ICSP™ header and the
USB interface. Therefore, communications with a host PC and emulator/programmer
connections do not need to be accounted for in determining an accurate current mea-
surement, as they are not included in the first place. Since J16 interrupts the V
to the board’s other components, always be certain to re-install the jumper when mea-
surements are not being taken.
3.3.3
The XLP 8-bit board includes a special 7-pin header (J14) for current measurement.
The PIC MCU VMCU and VBOARD jumpers (J15 and J16) ensure continuity of power
when connecting or disconnecting a current measurement device. Microchip provides
an optional XLP Current Measurement Cable (part number AC002023) as a convenient
way of connecting the header to an ammeter.
Note:
Programming Interfaces
PIC16LF1947 and PIC18F87K22 Current Measurement
Development Board Power Measurement
Ammeter Tool Header
Since the resistor is placed in series with the PIC MCU V
ing voltage drop may affect power calculations. Ensure calculations are
based on actual V
DD
, instead of the supplied board voltage.
DD
path, always be certain to re-install the jumper
DD
DS41581A-page 27
pin, the result-
DD
path