Skip to content

JTAG

Jump to bottom
ha7ilm edited this page Apr 28, 2016 · 3 revisions

https://raw.githubusercontent.com/ha7ilm/opendous/master/Current_Designs/Opendous_FT2232H_JTAG/Opendous_FT2232H_JTAG_Picture_Small.jpg

This is a DIY project with design files available in SVN. The design is 8mil/8mil trace/clearnace with minimum 20mil vias for cheap PCB fabrication. PCBs of this design can be purchased at cost through BatchPCB. The smallest component is 0805 to ease prototyping. A manufacturing tutorial will be posted at some point in the future.

It has Cortex Debug, ARM, and Xilinx JTAG headers. The associated required cables are: 0.05" 5x2 for Cortex Debug, 0.1" 10x2 for ARM, and 2mm 7x4 for Xilinx.

You can play with this design yourself as it is an OpenHardware board and all design materials are Creative Commons Attribution Licensed and made with the Open Source KiCAD EDA Suite.

The Opendous FT2232H JTAG uses Channel B for JTAG as only Channel A supports fast synchronous 245 mode which will be used for other functionality later on. If using the OpenOCD 0.5.0 release you will need to alter line 2216 of ft2232.c from

	/* default to INTERFACE_A */
	if(channel == INTERFACE_ANY) { channel = INTERFACE_A; }

to

	/* default to INTERFACE_B */
	if(channel == INTERFACE_ANY) { channel = INTERFACE_B; }

in order to use Channel B for JTAG. Recompile OpenOCD and install this modified version under a different name. The board will then function as a JTAGKey with the default FTDI VID and PID:

ft2232_device_desc "Dual RS232-HS"
ft2232_layout jtagkey
ft2232_vid_pid 0x0403 0x6010

Unfortunately channel selection is still not implemented via configuration scripts in OpenOCD.

See the libftdi Project for Open Source software to control this board.

Clone this wiki locally