Hi!
I have a big problem with connecting multiple masters to the OPB. I connected the Microblaze-Processor and a VGA-Controller to the bus. In the beginning everything works fine, but after maybe one second the whole system freezes. Even the FPGA seems to loose its configuration data. The voltage at the Done-Pin for example suddenly drops (not to 0V) and the video-timing generation fails (it only depends on the internal clock signal and has nothing to do with the bus). The code of the Microblaze is stored in the same SRAM the VGA-Controller uses for video data. When the code is stored in the internal memory I don't have any problems. The problems disappear when the VGA-Controller doesn't access the RAM.
Thanks a lot, Matthias Alles