Anthony Huereca

OpenSDA on Vybrid

Discussion created by Anthony Huereca Employee on Apr 24, 2013
Latest reply on Jul 13, 2015 by Edward Karpicz

OpenSDA is a low‐cost debug/programming interface embedded in certain Freescale evaluation boards. It handles debug communications between the PC and target via USB. It uses a Kinetis K20 50Mhz chip on the bottom of Vybrid tower board to run firmware developed by P&E that acts as a bootloader. This lets it run and load "apps" that add functionality to the OpenSDA circuit. For example, an app could allow debugging with DS‐5, or IAR. Or an app could turn OpenSDA into a virtual serial port so you can get serial data via a USB cable instead of using a RS232 cable. Or an app could allow drag‐and‐drop programming of flash devices like QuadSPI. The possibilities are very open ended. This is the same OpenSDA circuit found on Kinetis L boards.


The app will run every time power is applied to the OpenSDA circuit via J3.


To load a new app, hold down the reset button (SW3) while power is applied via J3, then the firmware will enter a bootloader mode, and enumerate as a mass storage device. You can then drag and drop the new "app" into that MSD to load it. Power cycle the device, and then the new app will run.


Currently there are two apps available for Vybrid:

  • CMSIS‐DAP ‐ For debugging with DS‐5 (default app on Rev A-F)
  • Virtual Serial Port ‐ For creating a serial‐to‐usb bridge (default app on Rev G)

In the future there will be a Mass Storage Device (MSD) app that will include virtual serial port capability, plus enumerate as a mass storage device on your computer to drag‐and‐drop binaries to be programmed into QuadSPI, NAND Flash, and more.


Other things to note:

  • Only RevG boards will have OpenSDA firmware
  • All other revisions (except RevA) only have a basic CMSIS‐DAP firmware loaded onto the K20, and does *not* have the OpenSDA firmware/bootloader. Older boards cannot be upgraded since this firmware can only be loaded at the board manufacturer. RevA boards do not have either firmware.
  • The OpenSDA circuit is only on the Vybrid tower board (TWR‐VF65GS10) and not other Vybrid boards.
  • The OpenSDA bootloader firmware is proprietary. However some of the apps, like the CMSIS-DAP app, have source available and can be programmed stand-alone into the K20 circuit. This may be useful if developing your own board.
    • However note that this connection will be noticeably slower than using a dedicated debugger like D-Stream or JLink.


More information on OpenSDA can be found at: