Nios II to SRAM via Tri-State Bridge

Hi, I had a quite similar problem in the following configuration.

- 16 bits SRAM on the board

- Custom SRAM component in SOPC builder

- cs, ws, oe, add, 16 bits data controlled by custom component

- beh, bel stuck to 0 in VHDL

- mapping of a0 => a1 in VHDL

All was functional when I was using "run configuration as" but the NIOS didn't boot in stand alone mode (boot copying from FLASH to SRAM).

I saw with Signal Tap that all accesses to SRAM during the boot were in 8 bits mode instead of 16 bits.

The solution was to add the control of beh and bel by the SRAM custom component, because it was not able to recognize a 16 bits SRAM with the 16 bits data bus specification !

Hope this helps.