What Is OSBDM?
OSBDM is an open source hardware/software/firmware design which provides low-speed debug communications for different Freescale processors. It is embedded within many of Freescale’s development board and tower cards:
The OSBDM design is community supported and developed. P&E Microcomputer Systems has become a key contributor to the project and has posted many drivers, utilities, fixes, and source code support for this design. P&E also has a broad range of low cost commercial products which represent a substantial feature set and speed improvement over OSBDM and come with support from P&E.
A typical OSBDM design configuration, in this case embedded into a Tower development board and connected to the PC via USB, is shown here:
The OSBDM based design usage is most compatible with the device evaluation phase as well as the start of development where an evaluation board is in use. In this stage, low cost access to a development system trumps speed and feature set. The OSBDM design not only provides debug communications but allows power to be provided to the Freescale processor under test. The development board shown above, with the OSBDM circuitry, generally has all circuitry needed to test many of the on-chip peripherals and write some basic code without requiring a dedicated debug hardware interface.
When moving into the design phase, most companies will produce their own application-specific hardware. This hardware generally would not contain the OSBDM circuitry and would likely include a very inexpensive debug connector instead. This debug connector will allow a hardware debug interface, such as P&E's USB Multilink Universal, to connect and debug/program the board as shown here:
A dedicated interface such as the Multilink has a much higher performance and more robust feature set than the OSBDM design. This is ideal for the development phase while still being very low cost. Since P&E’s software libraries are used by many of the tool vendors on the market to support OSBDM, and these libraries also support the Multilink, the transition from the embedded OSBDM to the USB Multilink is often transparent to the user. The transition to our Ethernet debug interfaces and production programming tools is also very simple.
The OSBDM design provides a launching pad for many customers starting new designs. This website provides utilities, documentation, and troubleshooting guides for OSBDM. Freescale maintains a forum where community provided support for OSBDM may be found. For those interested in understanding how OSBDM operates under the hood, the full source project is downloadable from this site as well.