Datasheet

Emulator User’s Guide for MPLAB X IDE
DS52085A-page 34  2013 Microchip Technology Inc.
3.5.4 Circuits That Will Prevent the Emulator From Functioning
Figure 3-9 shows the active emulator lines with some components that will prevent the
MPLAB REAL ICE in-circuit emulator system from functioning.
FIGURE 3-9: IMPROPER CIRCUIT COMPONENTS
For the Vpp/MCLR pin:
• Do not use capacitors on MCLR
– they will prevent fast transitions of VPP. A
simple pull-up resistor is generally sufficient.
For the programming pins (PGC/PGD), no componts should be connected, or more
specifically:
• Do not use pull-ups or pull-downs on PGC/PGD – they will affect the voltage
levels, since these lines already have 4.7 k pull-down resistors in the emulator.
• Do not use capacitors on PGC/PGD – they will prevent fast transitions on data
and clock lines during programming and debug communications, and may cause
debugging or programming failures
• Do not use diodes on PGC/PGD – they will prevent bidirectional communication
between the emulator and the target device.
Additional design information may be found in the “Development Tools Design Advi-
sory” (DS51764).
For other operational issues, see:
• Chapter 10. “Messages”
• Chapter 9. “Frequently Asked Questions (FAQ)”
• Section 10.3.6 “Debug Failure Actions” (Top Reasons Why You Can’t Debug)
• Section 12.6 “Loop-Back Test Board”
No!
No!
No!
No!
VPP/MCLR
PGC
PGD
1
5
4
ACTIVE STATUS
RESETFUNCTION
Emulator Pod
No!