Target Circuit Design Precautions
The figure below shows the active emulator lines with some example components that will prevent the MPLAB® REAL ICE™ In-Circuit Emulator system from functioning.
Figure: Improper Circuit Components
- Do not use capacitors on MCLR: they will prevent fast transitions of VPP.
- Do not use pull-ups on PGC/PGD: they will divide the voltage levels since these lines have 4.7 kΩ pull-down resistors in the emulator.
- Do not use multiplexing on PGC/PGD: they are dedicated to communications to the emulator.
- Do not use capacitors on PGC/PGD: they will prevent fast transitions on data and clock lines during programming and debug communications.
- Do not use diodes on PGC/PGD: they will prevent bidirectional communication between the emulator and the target device.
- Do not exceed recommended cable lengths: For acceptable cable lengths, see Section 11.5.2 “Modular Cable and Connector”.
Additional design information is available in "Development Tools Design Advisory".
For other operational issues, see "Emulator Self Test using the Loopback Test Board".