AXEL Lite SOM/AXEL Lite Evaluation Kit/Interfaces and Connectors/JTAG

History
ID#	Issue Date	Notes
11422	07/11/2020	New layout documentation
17019	22/09/2021	Add JTAG EVB connector

Contents

On board JTAG connectorEdit

JTAG signals are routed to a dedicated connector on the AXEL Lite PCB.

The connector is placed on the top side of the PCB, at the upper-right corner (please see the picture below).

J7 - SOM Connector's pinoutEdit

J7 footprint mates with Samtec FSI-110-03-G-S connector. The following table reports the connector's pinout:

JTAG connector

Pin#	Pin name	Function	ARM-20 JTAG	Notes
1	DGND	-	4,6,8,10,12,14,16,18,20	For example documented on Lauterbach specification
2	JTAG_TCK	-	9	-
3	JTAG_TMS	-	7	10K pull-up to 3V3 (BOARD_PGOOD driven signal)
4	JTAG_TDO	-	13	10K pull-up to 3V3 (BOARD_PGOOD driven signal)
5	JTAG_TDI	-	5	10K pull-up to 3V3 (BOARD_PGOOD driven signal)
6	JTAG_nTRST	-	3 (*)	10K pull-up to 3V3 (BOARD_PGOOD driven signal)
7	CPU_PORn	-	15 (*)	-
8	N.C.	-		-
9	N.C.	-		-
10	JTAG_VREF	-	1	3V3 (BOARD_PGOOD driven signal)

(*) keep the possibility to be unconnected

JD1 - EVB Connector's pinoutEdit

JD1 is a 10x1x2.54mm pinhole header. The following table reports the connector's pinout:

EVB JTAG connector

Pin#	Pin name	Function	Notes
1	DGND	-
2	JTAG_TCK	-	-
3	JTAG_TMS	-	10K pull-up to 3V3 (BOARD_PGOOD driven signal)
4	JTAG_TDO	-	10K pull-up to 3V3 (BOARD_PGOOD driven signal)
5	JTAG_TDI	-	10K pull-up to 3V3 (BOARD_PGOOD driven signal)
6	JTAG_nTRST	-	10K pull-up to 3V3 (BOARD_PGOOD driven signal)
7	JTAG_nRST	-	-
8	N.C.	-	-
9	N.C.	-	-
10	JTAG_VREF	-

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