JTAG and Bootable microSD cards

Overo COMs & JTAG

Instructions for creating a bootable microSD card are·in the How-To section of "Software Development", linked here

Note that each Gumstix Overo COM has JTAG pads on the underside of the Overo COM, located between the two 70-pin connectors. Further information can be found in the Overo Signals Document which can be downloaded here.

Information on using JTAG and J1-9 (GPIO_31)·- from both Texas Instruments and a Gumstix customer: (added July 20, 2010)

  • JTAG is highly usable. There is an issue to do with OMAP's JTAG emulation engine and the state of the EMU/n bits on dead-start. J1-9 (GPIO_31) needs to be pulled high on dead-start. See section 25.6.3 - Initial Scan Chain configuration (SPRUF98D-October 2009, OMAP35x Applications Processor Technical Reference Manual)
  • The initial scan chain configuration of the device is determined from the level of the EMU0 and EMU1 pins on the release of the POR. At POR, EMU0 and EMU1 are automatically configured as inputs. The EMU0 and EMU1 pins should be pulled high at POR to configure the initial scan chain of the device to TAP router-only mode.

Verdex Pro COMs & JTAG

Gumstix offers a·JTAG-pro expansion board for use with the verdex pro motherboards.

Verdex, Connex and Basix

Information can be found at: