Each column describes one supported combination of Corstone system, Ethos-U accelerator, and Vela memory mode for the Test-Ethos-U examples. For the complete process of adapting these settings to physical hardware, see the Ethos-U integration workflow.
| Setting | SRAM only | Shared SRAM |
|---|---|---|
| Target type | SSE-300-U55 | SSE-300-U55 |
| Solution | Test-Ethos-U55 | Test-Ethos-U55 |
| NPU | U55, 128 MACs | U55, 128 MACs |
| Vela INI | Model/vela.ini | Model/vela.ini |
| Vela system | Ethos_U55_High_End_Embedded | Ethos_U55_High_End_Embedded |
| Vela memory | Sram_Only | Shared_Sram |
| NPU_QCONFIG | 1 | 2 (default) |
| NPU_REGIONCFG_0 | 1 | 3 (default) |
| NPU_REGIONCFG_1 | 0 | 0 (default) |
| NPU_REGIONCFG_2 | Unused | Unused |
| ETHOS_CACHE_SIZE | Not used | Not used |
| ethos_model | SRAM_VM0 / RAM1 via AXI0 | DDR4_3 / ROM2 via AXI1 |
| ethos_arena | SRAM_VM0 / RAM1 via AXI0 | SRAM_VM0 / RAM1 via AXI0 |
| ethos_cache | Unused | Unused |
| Setting | SRAM only | Shared SRAM | Dedicated SRAM |
|---|---|---|---|
| Target type | SSE-300-U65 | SSE-300-U65 | SSE-300-U65 |
| Solution | Test-Ethos-U65 | Test-Ethos-U65 | Test-Ethos-U65 |
| NPU | U65, 256 MACs | U65, 256 MACs | U65, 256 MACs |
| Vela INI | Model/vela.ini | Model/vela.ini | Model/vela.ini |
| Vela system | Ethos_U65_Embedded | Ethos_U65_Embedded | Ethos_U65_Mid_End |
| Vela memory | Sram_Only | Shared_Sram | Dedicated_Sram_384KB |
| NPU_QCONFIG | 1 | 2 (default) | 2 |
| NPU_REGIONCFG_0 | 1 | 3 (default) | 3 |
| NPU_REGIONCFG_1 | 0 | 0 (default) | 2 |
| NPU_REGIONCFG_2 | Unused | Unused | 1 |
| ETHOS_CACHE_SIZE | Not used | Not used | 393216 bytes |
| ethos_model | SRAM_VM0 / RAM1 via AXI0 | DDR4_3 / ROM2 via AXI1 | DDR4_3 / ROM2 via AXI1 |
| ethos_arena | SRAM_VM0 / RAM1 via AXI0 | SRAM_VM0 / RAM1 via AXI0 | DDR4_1 / RAM0 via AXI1 |
| ethos_cache | Unused | Unused | SRAM_VM0 / RAM1 via AXI0 |
| Setting | SRAM only | Shared SRAM | Dedicated SRAM |
|---|---|---|---|
| Target type | SSE-320-U85 | SSE-320-U85 | SSE-320-U85 |
| Solution | Test-Ethos-U85 | Test-Ethos-U85 | Test-Ethos-U85 |
| NPU | U85, 256 MACs | U85, 256 MACs | U85, 256 MACs |
| Vela INI | Model/vela.ini | Model/vela.ini | Model/vela.ini |
| Vela system | Ethos_U85_SYS_DRAM_Mid | Ethos_U85_SYS_DRAM_Mid | Ethos_U85_SYS_DRAM_Mid |
| Vela memory | Sram_Only | Shared_Sram | Dedicated_Sram_384KB |
| NPU_QCONFIG | 1 | 2 (default) | 2 |
| NPU_REGIONCFG_0 | 1 | 3 (default) | 3 |
| NPU_REGIONCFG_1 | 0 | 0 (default) | 2 |
| NPU_REGIONCFG_2 | Unused | Unused | 1 |
| ETHOS_CACHE_SIZE | Not used | Not used | 393216 bytes |
| ethos_model | SRAM_VM0 / RAM1 via AXI_SRAM | DDR4_3 / ROM2 via AXI_EXT | DDR4_3 / ROM2 via AXI_EXT |
| ethos_arena | SRAM_VM0 / RAM1 via AXI_SRAM | SRAM_VM0 / RAM1 via AXI_SRAM | DDR4_1 / RAM0 via AXI_EXT |
| ethos_cache | Unused | Unused | SRAM_VM0 / RAM1 via AXI_SRAM |
The values marked default are supplied by the selected Generic Ethos-U driver configuration when the board layer does not override them. The SRAM-only U55 configuration must override the shared-SRAM defaults.
After selecting a column, regenerate the solution's *.cbuild-mlops.yml file and convert both models before building:
| NPU | Conversion command |
|---|---|
| U55 | python script/model-converter.py Test-Ethos-U55.cbuild-mlops.yml |
| U65 | python script/model-converter.py Test-Ethos-U65.cbuild-mlops.yml |
| U85 | python script/model-converter.py Test-Ethos-U85.cbuild-mlops.yml |
NOTES
- The generated files under Model/ are shared by all solutions. Always reconvert them after changing the target or Vela configuration.
- ROM2 is a read-only linker execution region backed by DDR4_3; it is not physical ROM.
- Shared_Sram places the command stream and constants in external memory and the writable tensor arena in SRAM. It does not use a dedicated Vela arena cache.
- Dedicated_Sram_384KB places the model and writable arena in external DDR4 and reserves 384 KiB of SRAM as the Vela arena cache. ETHOS_CACHE_SIZE must equal Vela's arena_cache_size of 393216 bytes.
- Ethos-U55 does not use Dedicated_Sram because its AXI1 interface is read-only, while that mode requires a writable arena on Axi1.
