ICD 4: Standard Communication

The main interface to the target processor is via standard communication. It contains the connections to the high voltage (VPP), VDD sense lines, and clock and data connections that are required for programming and connecting with the target devices.

The VPP high-voltage lines can produce a variable voltage that can swing from 0-14 V to satisfy the voltage requirements of the specific emulation processor.

The VDD sense connection draws very little current from the target processor. The actual power comes from the MPLAB® ICD 4 In-Circuit Debugger system, as the VDD sense line is used as a reference only to track the target voltage. The VDD connection is isolated with an optical switch.

The clock and data connections are interfaces with the following characteristics:

  • Clock and data signals are in High-Impedance mode (even when no power is applied to the MPLAB ICD 4 In-Circuit Debugger system)
  • Clock and data signals are protected from high voltages caused by faulty target systems, or improper connections
  • Clock and data signals are protected from high current caused by electrical shorts in faulty target systems
Figure 1: 6-pin Standard Pinout

Table: Electrical Logic

Logic Inputs VIH = VDD x 0.7 V (min.)
VIL = VDD x 0.3 V (max.)
Logic Outputs VDD = 5 V VDD = 3 V VDD = 2.3 V VDD = 1.65 V
VOH = 3.8 V min. VOH = 2.4 V min. VOH = 1.9 V min. VOH = 1.2 V min.
VOL = 0.55 V max. VOL = 0.55 V max. VOL = 0.3 V max. VOL = 0.45 V max.

Modular Cable and Connector

For standard communication, a modular cable connects the debugger and the target application. The specifications for this cable and its connectors are listed below.

Modular Connector Specification:

  • Manufacturer, Part Number – AMP Incorporated, 555165-1
  • Distributor, Part Number – Digi-Key, A9031ND

Figure 2 shows how the modular connector pins for an application correspond to the microcontroller pins. This configuration provides full in-circuit debugger functionality.

Figure 2: Modular Connector Pinout of Target Board

Modular Plug Specification:

  • Manufacturer, Part Number – AMP Incorporated, 5-554710-3
  • Distributor, Part Number – Digi-Key, A9117ND

Modular Cable Specification

Manufacturer, Part Number – Microchip Technology, 07-00024 The length of this cable (L) is 6 inches. It is not recommended that you use a modular cable longer than 6 inches to avoid potential communication problems.

Figure 3: Modular Cable
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