MPLAB® ICD 4 In-Circuit Debugger

The debugger consists of an internal main board and an external USB connector, RJ-45 type connector, and a power connector. On the face of the debugger enclosure is an indicator light bar composed of two LEDs.

Main Board

The main board includes the following features:

  • a 32-bit microcontroller using an ARM® Cortex®-M7 core
  • a USB 2.0 interface capable of USB speeds of 480 Mbps
  • an FPGA for general system control and increased communication throughput
  • an SRAM for holding the program code image. This image is used for programming on-board Flash device.
  • two LEDs

Indicator Lights (LEDs)

The expected start-up sequence for the MPLAB® ICD 4 debugger is:

  1. Purple - steady on for approximately 3 seconds.
  2. Blue - flashing for approximately 2 seconds while the debugger runs a power-on self-test.
  3. Blue - steady on. The debugger is ready.
  4. The "LED and Bootloader Error Descriptions" table advises how to read the indicator lights.
Left LED Right LED Description
Normal Modes
Blue Blue Power is connected; debugger on standby
Orange Blue Power target circuit from ICD 4 checked (Power)
Green Blue Power target circuit from ICD 4 unchecked (Power)
Purple Purple Bootloader is running
Yellow Yellow Debugger is busy
Red Red An operation has failed
Purple Purple Fast blink indicates the time window for forcing the debugger into Bootloader mode
Bootloader Errors
Purple Red, slow blink Problem accessing the debugger’s serial EEPROM
Purple Red, fast blink Bootloader API commands cannot be processed
White, fast blink White, fast blink A runtime exception occurred in the tool firmware
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