Create an emulation model for the Tomu.im board

[mithro]

Tomu is an open source, tiny little ARM microcontroller that fits inside your USB port.

The Tomu uses an SiLabs EFM32HG309 part. It looks like there is already quite a bit of support for the SiLabs EFM32 series.

The closest platform I found was for the EFM32HG350.

I think that means it would be as simple as;

• Copying the efm32hg350.repl file to efm32hg309.repl and tweaking some values
• Adding the efm32hg USB device interface.
• Creating a board configuration.

The USB device is described as;

3.1.10 Low Energy USB

The unique Low Energy USB peripheral provides a full-speed USB 2.0 compliant device controller and PHY with ultra-low current consumption.
The device supports both full-speed (12 MBit/s) and low speed (1.5 MBit/s) operation, and includes a dedicated USB oscillator
with clock recovery mechanism for crystal-free operation. No external components are required. The Low Energy Mode ensures the
current consumption is optimized and enables USB communication on a strict power budget. The USB device includes an internal dedicated
descriptor-based Scatter/Gather DMA and supports up to 3 OUT endpoints and 3 IN endpoints, in addition to endpoint 0. The onchip
PHY includes software controllable pull-up and pull-down resistors.

I believe this USB controller is very similar to others in the EFM32HG series. It says

The features of the EFM32HG309 is a subset of the feature set described in the EFM32HG reference Manual.
| USB | Full configuration | USB_VREGI, USB_VREGO, USB_DM, USB_DMPU, USB_DP |

The schematic of the Tomu board can be found here.

[mithro]

The config for platforms/cpus/silabs/ezr32/ezr32hg320.repl might also be relavent.