1. When accessing LMB, why do I see activity on the OPB signals?
2. What would happen if another master on the bus performed a transaction ?
1. MicroBlaze does not know if an access is for the LMB or the OPB. Consequently, two simultaneous requests are performed. The LMB must respond in one clock cycle. If the response is an access for the LMB, MicroBlaze removes the transaction on the OPB.
2. MicroBlaze does not simply take over the OPB bus; MicroBlaze sends a proper bus request to the arbiter. It is not an issue if there is another master on the bus.