DS51795A Datasheet, PDF (24/98 Pages) Microchip Technology – PICkit™ 3 Programmer/Debugger

PICkit™ 3 User’s Guide
FIGURE 2-6:
PROPER CONNECTIONS FOR PROGRAMMING
Programming
Voltage
+5V
1
Internal Circuits
4.7 kΩ
5
4
4.7 kΩ
VDD
VPP/MCLR
PGC
PGD
VSS
A simplified diagram of some of the internal interface circuitry of the PICkit 3
programmer/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 VPP/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.
2.6 REQUIREMENTS FOR DEBUGGING
To debug (set breakpoints, see registers, etc.) with the PICkit 3 programmer/debugger
system, there are critical elements that must be working correctly:
• The debugger must be connected to a PC. It must be powered by the PC via the
USB cable, and it must be communicating with the MPLAB IDE software via the
USB cable. See Chapter 3. “Installation” for details.
• The debugger must be connected as shown to the VPP, PGC and PGD pins of the
target device with the modular interface cable (or equivalent). VSS and VDD are
also required to be connected between the debugger and target device.
• The target device must have power and a functional, running oscillator. If the
target device does not run, for any reason, the PICkit 3 programmer/debugger
cannot debug.
• The target device must have its configuration words programmed correctly:
- The oscillator Configuration bits should correspond to RC, XT, etc., depending
upon the target design.
- For some devices, the Watchdog Timer is enabled by default and needs to be
disabled.
- The target device must not have code protection enabled.
- The target device must not have table read protection enabled.
• LVP should be disabled.
Once the above conditions are met, you may proceed to the following:
• Sequence of Operations Leading to Debugging
• Debugging Details
DS51795A-page 20
© 2009 Microchip Technology Inc.