Read and write 16 bits device via Avalon

Hello mountain8848,

Here more details about my SOPC Builder component.

1. I was using "Memory" addressing mode, now I switch to "Register".

2. To have correct timing for the USB device, I use a clock @ 36MHz for this SOPC Builder component, this clock is not needed by the USB device, it just need Read, Write and Chipselect signals. Is there another and/or perhaps better way to specify bus timings ?

3. I use Avalon Slave interface. I think it's the best choice, or not ?

4. For the address signals, I carried out serveral tests.

First, after reading page 6-26 from Quartus II Handbook, Volume 4, I was thinking that Avalon address signal allways presents a byte address. So I put 3 address line on Avalon side (eg. address(2 downto 0)).

address(0) --> Not used because data bus with is 16 bits

address(1) --> A0 from USB Device

address(2) --> For selection between USB Device and internal registers.

But after some tests I saw that address(0) is not Avalon A0 signal but seems to be A1 !

So I change my address bus with on Avalon side to address(1 downto 0).

address(0) --> A0 from USB Device

address(1) --> For selection between USB Device and internal registers.

Now I use IORD() and IOWR() macros and this configuration seems to work.