Hi,
Currently I'm working on a OPB to ISA bridge to be included as a peripheral in a Microblaze system. To verify that the bridge works, I've also made a GPIO that is connected as a peripheral on the ISA bus. The ISA data bus is bidirectional and is thus implemented as a tristate port. Since the data port on the ISA GPIO also is bidirectional, that is also implemented as a tristate. The problem is that when the two tristate signals are connected in the system.mhs file (data = isa_sd) XST interprets that to connect the isa_sd_i with data_i, isa_sd_o with data_o, and isa_sd_t with data_t. I have also tried to separate the data ports on the GPIO side, but I haven't worked out how to specify that isa_sd_o should be connected to data_i and isa_sd_i to data_o.
Does anyone with more experience on this matter than me have any good suggestions on how to solve the problem?
Johan