J-Link Microchip Adapter


The SEGGER J-Link Debug Module is designed to connect to its targets through a 24 pin cable, provided with the J-Link. However, Microchip development boards that support JTAG use a 14 pin connector supporting four wire JTAG. In addition, most Microchip development boards provide the proprietary In-Circuit Serial Programming (ICSP) 2-wire interface through an RJ-11 connector.

SEGGER provides an adapter that bridges the gap between the 24 pin connection on the J-Link to the 4-wire and 2-wire connections available on Microchip development boards. For J-Link Microchip Adapter purchasing details please visit the Segger adapter products page.


4-Wire JTAG

For those Microchip development boards that support 4-wire JTAG, the adapter is used with the included 14 pin connector. Note the location of PIN 1 (in this case, at the top of the cable) and that the ribbon cable designates this pin with a color different from the rest of the cable.


Because of the nature of a ribbon connector, determining the correct orientation can be a challenge. The illustration below shows the orientation of the connector between the J-Link Microchip Adapter and the Microchip Explorer 16 Development Board. Note that unfortunately, there really is no connection that will avoid twisting the cable.


2-Wire ICSP (JTAG emulation)

The J-Link Debug module also supports the Microchip ICSP 2-wire interface. In this case, the TCK and TDI pins are connected to the SCK and SDA pins in what is effectively a JTAG emulation. This allows the use of the SEGGER J-Link with all Microchip development boards that do not support JTAG but do support the ICSP RJ-11 connection. Since the RJ-11 connections are naturally keyed, there is no question about orientation - simply snapping the connector into any Microchip development board that supports ICSP through the RJ-11 connector guarantees a proper connection.


If you are creating your own board, the illustration below indicates the orientation of the RJ11 pins:

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