Part 3 of a series on building a native Razer mouse controller for macOS.
We have the envelope from part 2. Now the commands that actually do something: DPI and lighting. The DPI one is easy. The color one taught me the most useful lesson in this whole project, which is that the device telling you 0x02 (OK) is not the device telling you it did what you wanted.
Setting DPI
Command class 0x04, id 0x05, data_size 0x07.
The value is the raw DPI, not divided by anything. 800 DPI is 0x0320, split into a high byte and a low byte. The mouse stores X and Y sensitivity separately, so you send the pair twice.
