Programmers and Debuggers

JTAG Pinout

SAM-ICE has a JTAG connector compatible to ARM’s Multi-ICE. The JTAG connector is a 20-way Insulation Displacement Connector (IDC) keyed box header (2.54mm male) that mates with IDC sockets mounted on a ribbon cable.

Figure 1. JTAG Pinout

The table below lists the SAM-ICE JTAG pinouts.

Table 1. JTAG Pinout
Pin Signal Type Description
1 VTref Input

This is the target reference voltage.

It is used to check if the target has power, to create the logic-level reference for the input comparators and controls the output logic levels to the target. It is normally fed from VDD on the target board and must not have a series resistor.

2 Vsupply NC

This pin is not connected in SAM-ICE. It is reserved for compatibility with other equipment. Connect to VDD or leave open in target system.

3 nTRST Output

JTAG Reset. Output from SAM-ICE to the Reset signal on the target JTAG port. Typically connected to nTRST on the target CPU. This pin is normally pulled HIGH on the target to avoid unintentional resets when there is no connection.

4 GND - Common ground
5 TDI Output

JTAG data input of the target CPU. It is recommended that this pin is pulled to a defined state on the target board. Typically connected to TDI on target CPU.

6 GND -

Common ground

7 TMS Output

JTAG mode set input of target CPU. This pin should be pulled up on the target. Typically connected to TMS on target CPU.

8 GND -

Common ground

9 TCK Output

JTAG clock signal to target CPU. It is recommended that this pin is pulled to a defined state on the target board. Typically connected to TCK on target CPU.

10 GND -

Common ground

11 RTCK NC

Input Return test clock signal from the target. Some targets must synchronize the JTAG inputs to internal clocks. To assist in meeting this requirement, a returned and re-timed TCK can be used to dynamically control the TCK rate. SAM-ICE supports adaptive clocking, which waits for TCK changes to be echoed correctly before making further changes. Connect to RTCK if available, otherwise to GND.

12 GND -

Common ground

13 TDO Input

JTAG data output from target CPU. Typically connected to TDO on target CPU.

14 GND -

Common ground

15 RESET I/O

Target CPU reset signal

16 GND -

Common ground

17 - NC

This pin is not connected in SAM-ICE

18 GND -

Common ground

19 - NC

This pin is not connected in SAM-ICE

20 GND -

Common ground