Idea for connecting FPGA to Data BUS

[djnik1362]

hi

I have a 8-bit data BUS that connect several Buffers and Latches
to an AVR microcontrller.

I want to connect FPGA to BUS so i can communicate with FPGA .

I decide to use a 8-bit latch to feed data BUS to FPGA as input and
a 8-bit buffer to get data from FPGA and send to data BUS.

I could use a "inout" structure in FPGA but i prefer using above structure.

Suppose i have 5 software block in FPGA that have an 8-bit output that
must fed to BUS. I connect A15-A13 address BUS to FPGA so i can choose
8 block from FPGA .


I use a 8x1 8-bit MUX in FPGA that with A15-A13 signals and RD signal choose
blocks output to connect to BUS.

I decide to create 3 software blocks that have 8-bit inputs from Data BUS.
My idea is to use a DEMUX at FPGA and 3 8-bit D-FF for each block that
with "posedge" of WR signal latch-up data BUS to proper D-FF.

I write my code in Verilog and simulate this structure with Xilin ISE 9.1 and
it work correctly.

I need your ideas that if this configuration works in practice .

Thanks for your support.

 

[FvM]

Add FPGA to Data BUS

Sounds promising so far. Why don't you simply try - or use a simulator?

 

[djnik1362]

Re: Add FPGA to Data BUS

Sounds promising so far. Why don't you simply try - or use a simulator?

Because our PCB is very complicated and we don't have enough time.
I simulate this with Xilinx ISE and it work but i need some practical ideas
that confirm my design.

What your idea about connecting FPGA to Data BUS without respect to my design ?

Thanks for your support.

 

[farhada]

Re: Add FPGA to Data BUS

You can connect the FPGA to any BUS without the need to a buffer. It simplifies the design and make it easier to make changes in the future.

Long time ago, we had a board with 2 TI DSPs, and 2 Motorola Power PC processors together with 2 memory blocks , we used a large FPGA to connect them together and act like a common memory for all the units. It was hard to achieve but it worked properly.

Best regards,
/Farhad