Hi,
We're currently developing a custom motor control application board using the F28335 DSP. The necessary software is being developed and tested on a spectrum Digital eZdsp F28335 and works fine so far. This week we wanted to start testing the software on the application board. This board features a lot of the F28335 reference designs including the JTAG connection reference-design. So we tried to connect it to a PC via a Spectrum Digital USB XDS510 emulator to program it using Code Composer Studio 3.3. Unfortunately we expirienced unexpected trouble doing so and had to find out that the processor appears to be locked (all PWL1-8 registers read back 0x0000 and there is no way to program the device). Here it's necessary to say, that we only tried to program into RAM and not into Flash. Flash wouldn't work anyway, because the device is locked and wants a password we don't have and never set. We double checked the JTAG-Connection, Memory Mapping and Boot-Mode-Options. We tried programming the device using another emulator (XDS 510 PP), and verified that the software is ok by programming it onto the eZdsp using its USB connection, the XDS510 USB and the XDS 510 PP (everything works fine). We also used CCS single-step feature to ensure, that the DSP itself is fine (it runs around in boot rom).
So meanwhile we are running out of ideas and have absolutely no idea how the F28335 gets locked and how to make sure that it won't happen again, as we lost 4 DSPs and two 6-Layer-Application-Boards already. The only thing we're not sure about is, whether we need to have some special settings in the emulator-configuration or in CCS. So we'd be happy about any suggetions and appreciate any help!
Thanks
