lowRISC / lowRISC/lowrisc-fpga

Increase Block RAM in LowRISC 0.2

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Dominant language
C
Stars
56
Forks
16
PR merge metrics
No merged PRs in 30d

Description

What is the correct procedure to increase the block ram in lowrisc version 0.2 to run large bare metal applications?
I changed `localparam BRAM_ADDR_WIDTH = 16;` to `localparam BRAM_ADDR_WIDTH = 17;` Everything compiles and I can see FPGA utilization has increased. When I compile the bare metal program I get this error in bmm2mmi
```
WARNING: [Vivado 12-180] No cells matched 'ram_reg_15'.
ERROR: [Common 17-55] 'get_property' expects at least one object.
Resolution: If [get_] was used to populate the object, check to make sure this command returns at least one valid object.
```

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First steps

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  3. Fork the repository and make your change on a branch.
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Research direction

Start by reviewing the BRAM_ADDR_WIDTH change and the bmm2mmi error, then reproduce the bare metal compilation flow for LowRISC 0.2. Done means the increased block RAM is recognized by the generated memory files and a large bare metal application compiles without the Vivado missing-cell error.

Written by the indexing model from the issue text.

Assessment

Tech stack
c
Domain
embedded-iot
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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