DCCM response stalling feature disabled

[shahzaibk23]

The Core doesn't wait for the dccm response anymore. This feature was part of the core in initial releases.

But it seems to have been disabled some time ago, because of unknown reasons, as can be seen in this commit.

Need to re-enable it, in order to make it generally compatible. OR else it should be Out of Order.

For current development context, we require that feature to be re-enabled.

Future Note: Make it Out of Order

[shahzaibk23]

The issue is partially resolved. Now the core constantly sends request until it receives a response and load word is also not working as it should.

Follow below steps to use SoC-Now to connect NRV and SRAM using Wishbone bus (which by default takes 3 cycles to complete an operation).

• git clone https://github.com/merledu/SoC-Now-Generator
• cd SoC-Now-Generator
• git checkout dev_generic_arch
• Copy the instructions from here and paste into an instructions.txt file in the SoC-Now-Generator root.
• Add NOPs (hex 00000013) at the end of instructions, as required by NRV to function.
• Then to compile the SoC and generate VCD using sbt "testOnly GeneratorTest -- -DwriteVcd=1 -DprogramFile=instructions.hex"
• To Debug the course of instructions, refer here

[shahzaibk23]

Fixed the load word issue in this commit.

The continuous request sending bug is still there, but it is harmless for now. Caravan turns the bus ready off once it gets the request, until the response is sent back it stays off, so the recurring request that NRV sends on while waiting for response to come, gets ignored by the bus.

It is not an immediately needed bug fix but should be done in Future.