JTAG Connector PinOut Diagram(with different Interfaces)

The JTAG (Joint Test Action Group) connector is also known as the JTAG header or JTAG port. It is a standardized interface used for testing, programming, and debugging electronic devices, especially integrated circuits (ICs) and printed circuit boards (PCBs). It provides a means to access and control the internal circuitry of a device for various purposes. The JTAG connector typically consists of multiple pins or contacts arranged in a specific pattern. Here in this article, we are going to see PinOut Diagrams of different types of JTAG Connectors.

The above Pin Diagram has the following JTAG Connectors,

Connector	Pin Count	Pin Name	Description
ARM JTAG 8-Pin Interface	8	See the pin names in the above pin diagram	Standard JTAG interface with 8 pins.
ARM JTAG 14-Pin Interface	14	See the pin names in the above pin diagram	Standard JTAG interface with 14 pins.
ARM JTAG 20-Pin Interface	20	See the pin names in the above pin diagram	Standard JTAG interface with 20 pins.
ARM CoreSight 10-Pin Interface	10	See the pin names in the above pin diagram	CoreSight interface with 10 pins.
ARM CoreSight 20-Pin Interface	20	See the pin names in the above pin diagram	CoreSight interface with 20 pins.
OCDS 16-Pin Interface	16	See the pin names in the above pin diagram	On-Chip Debug System interface with 16 pins.
ST 14-Pin Interface	14	See the pin names in the above pin diagram	ST interface with 14 pins.
TI JTAG 14-Pin Interface	14	See the pin names in the above pin diagram	Texas Instruments JTAG interface with 14 pins.

As you see in the above pinout diagram, there are various types of JTAG connectors and have different numbers of pins. The specific pinout and functions of a JTAG connector can vary depending on the device, connector specification, or manufacturer, but here is a general overview of the commonly used pins in a JTAG connector:

TCK (Test Clock): This pin provides the clock signal for synchronizing the data transfer between the JTAG interface and the device being tested or programmed.

TMS (Test Mode Select): This pin controls the operation mode of the JTAG interface. It determines whether the device is in the test mode or the normal operational mode.

TDI (Test Data Input): This pin is used to input test data into the device during testing or programming operations.

TDO (Test Data Output): This pin is used to output test data from the device during testing or programming operations.

TRST (Test Reset): This optional pin is used to reset the device under test or to reset the JTAG interface itself.

Ground (GND): This pin serves as the reference ground for the JTAG interface and ensures proper grounding of the signals.