I had some internal training I needed to prep for but back to this project. 

When choosing chips for a link, the unique thing is that you have to choose both a serializer and a deserializer for the link. When it comes to GMSL, there are a few flavors of each but I'll spare you the sales pitch. I definitely wanted one camera but thought about the expansion to a second camera. ADI offers a single, dual, and quad deserializer so I chose the dual to allow for the second camera link. Therefore, the serdes pair chose was the MAX96717 and MAX96716A. Feel free to reach out if you have questions on the other chips.

These chips were chosen because they offer some new features like Reference clock Over Reverse channel (RoR), Tunnel mode, and Forward Error Correction (FEC). All of which simplify and robustify the serial link. There's other nice features we'll discuss later in the project.

With these two, we'll be leveraging the reverse channel which allows us to talk I2C over the cable while simultaneously transmitting high bandwidth video data on the forward channel and low latency (microsecond) communication on the reverse channel. This is an asymmetric, full duplex communication protocol meaning there is a lot of bandwidth available in one direction and typically a little bit of bandwidth in the other direction but both directions can communicate at the same time.

Additionally, I'll be leveraging the power over coax (PoC) capability of GMSL and using a Power Management IC (PMIC) on the camera to create a bunch of voltages needed on the remote camera from a single voltage. In the GMSL Hardware Design Guide, we detail how this is chosen and I'll address it in more detail in a later log.

But the PMIC chosen is the MAX20049 from the Automotive Power group at ADI. The nice thing about this PMIC is that it has a lot of orderable part numbers with different configurations so it's preprogrammed to boot up with certain power rails. This is helpful because most cameras need similar rail voltages. For this project, I chose the MAX20049ATED variant. The voltages are 3.3V for GMSL and QWIIC, 2.8V for camera sensors, 1.8V for GMSL and camera sensors, and 1.2V for GMSL and camera sensors.

So with the serializer, deserializer, and camera PMIC chosen, it's onto starting the schematics!