On Mon, Dec 6, 2010 at 12:33 PM, Øyvind Harboe <[email protected]> wrote: > I believe that there might exist a safe default or autodetection > scheme for a specific family of parts. > > Such parts could use a common configuration file which > did the autodetect/set the robust default frequency. > > The responsibility for deciding how to deal with JTAG clk > is still firmly in the board configuration file though. The > board config file might ultimately decide directly or > indirectly to use a family-default or autodetect scheme, > that was a decision made by the board config file. > > -- > Øyvind Harboe > > Can Zylin Consulting help on your project? > > US toll free 1-866-980-3434 / International +47 51 63 25 00 > > http://www.zylin.com/zy1000.html > ARM7 ARM9 ARM11 XScale Cortex > JTAG debugger and flash programmer > _______________________________________________ > Openocd-development mailing list > [email protected] > https://lists.berlios.de/mailman/listinfo/openocd-development >
All device vendors should provide BSDL files for their devices which specify the maximum TCK speed the device can support. This can be used to create an auto-configuration that is fairly easy to use and robust. An example of this is the Xilinx programming tools. They do an initial shift at a low speed to find the JTAG ID's of each device. Once the device IDs are found a search is done against the BSDL files to find a matching description. Once that is complete the lowest maximum JTAG speed is used as an initial configuration based on the BSDL information. As an added benefit the JTAG instruction lengths are also defined in the BSDL so it does not need to be configured manually. If you see failures then you have the option of manually lowering the maximum JTAG frequency which overrides the BSDL files. -Karl _______________________________________________ Openocd-development mailing list [email protected] https://lists.berlios.de/mailman/listinfo/openocd-development
