MPLAB
®
ICD 3 User’s Guide for MPLAB X IDE
DS50002081B-page 20
2012-2014 Microchip Technology Inc.
2.5
DEBUGGING
There are two steps to using the MPLAB ICD 3 In-Circuit Debugger system as a
debugger. The first requires that an application be programmed into the target device
(MPLAB ICD 3 can be used for this). The second uses the internal in-circuit debug
hardware of the target Flash device to run and test the application program. These two
steps are directly related to the MPLAB X IDE operations:
1.
Programming the code into the target and activating special debug functions
(see the next section for details).
2.
Using the debugger to set breakpoints and run.
If the target device cannot be programmed correctly, the MPLAB ICD 3 In-Circuit
Debugger will not be able to debug.
shows the basic interconnections required for programming. Note that this
, but for the sake of clarity, the V
DD
and V
SS
lines from the
debugger are not shown.
FIGURE 2-6:
PROPER CONNECTIONS FOR PROGRAMMING
A simplified diagram of some of the internal interface circuitry of the MPLAB ICD 3
In-Circuit Debugger is shown. For programming, no clock is needed on the target
device, but power must be supplied. When programming, the debugger puts
programming levels on V
PP
/MCLR, sends clock pulses on PGC and serial data via
PGD. To verify that the part has been programmed correctly, clocks are sent to PGC
and data is read back from PGD. This conforms to the ICSP protocol of the device
under development. See the device programming specification for details.
+5V
Programming
4.7 k
4.7 k
V
PP
/MCLR
PGC
PGD
1
5
4
Internal Circuits
V
SS
V
DD
Voltage