I have a microblaze design with a single bram for data and instructions connected via 2 lmb_cntrls to the processor.
I have an mdm connected to the debug port.
Connected to the plb I have an MPMC which is connected to my off-chip DDRII SDRAM and a bram connected via a xps_cntrl. I also have an xps_gpio which connects the init_done signal of the MPMC to the PLB.
I have been trying to 'probe' the design using xmd and I found that while I can read and write to the processors registers and the data/instruction bram I cannot write to any of the peripherals/memory attached to the PLB. I can read from all the address ranges for the SDRAM, Bram and the GPIO but all I get is zeros and if I try to write values in they don't 'stick'.
My single PLB is connected to both the IPLB and DPLB ports on the microblaze.
I'm using edk 10.1
Could anyone suggest what might be wrong with my PLB or how I could diagnose the problem?