AT91SAM-ICE User Guide
2-1
6206B–ATARM–04-Mar-08
Section 2
Hardware
2.1
JTAG Connector
A SAM-ICE connector is a 20-way Insulation Displacement Connector (IDC) keyed box header (2.54 mm
male) that mates with IDC sockets mounted on a ribbon cable.
2.1.1
Pinout
lists the SAM-ICE JTAG pinout.
Table 2-1. 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 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 retimed 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.
