Microchip Technology PICkit 3 Starter Kit DV164130 DV164130 User Manual
Product codes
DV164130
PICkit™ 3 User’s Guide
DS51795A-page 18
© 2009 Microchip Technology Inc.
FIGURE 2-4:
STANDARD CONNECTION TARGET CIRCUITRY
2.4.3
Target Powered
In the following descriptions, only three lines are active and relevant to core debugger
operation: pins 1 (V
operation: pins 1 (V
PP
/MCLR), 5 (PGC) and 4 (PGD). Pins 2 (V
DD
) and 3 (V
SS
) are
shown on Figure 2-4 for completeness. PICkit 3 has two configurations for powering
the target device: internal debugger and external target power.
the target device: internal debugger and external target power.
The recommended source of power is external and derived from the target application.
In this configuration, target V
In this configuration, target V
DD
is sensed by the debugger to allow level translation for
the target low voltage operation. If the debugger does not sense voltage on its V
DD
line
(pin 2 of the interface connector), it will not operate.
2.4.4
Debugger Powered
The internal debugger power is limited to 30 mA. This may be of benefit for very small
applications that have the device V
applications that have the device V
DD
separated from the rest of the application circuit
for independent programming, but is not recommended for general usage as it imposes
more current demands from the USB power system derived from the PC.
more current demands from the USB power system derived from the PC.
Not all devices have the AV
DD
and AV
SS
lines, but if they are present on the target
device, all must be connected to the appropriate levels in order for the debugger to
operate. They cannot be left floating.
operate. They cannot be left floating.
In general, it is recommended that all V
DD
/AV
DD
and V
SS
/AV
SS
lines be connected to
the appropriate levels. Also, devices with a V
CAP
line (PIC18FXXJ for example) should
be connected to the appropriate capacitor or level.
V
DD
V
PP
/MCLR
PGC
PGD
V
SS
AV
DD
AV
SS
2
1
5
4
3
User Reset
4.7K-10K
Interface
Connector
Application
PC Board
Device
Note:
The interconnection is very simple. Any problems experienced are often
caused by other connections or components on these critical lines that
interfere with the operation of the PICkit 3 programmer/debugger, as
discussed in the following section.
caused by other connections or components on these critical lines that
interfere with the operation of the PICkit 3 programmer/debugger, as
discussed in the following section.