Commenting on this post I got interested in the capabilities of the i.m8m and it’s interfaces. I would like to know which interface purism wants to use for which components. As far as i can see there are the following planed components which need to be connected.
Wi-Fi / BT
WWAN (modem) probably including GPS
front and rear camera
sensors (Accelerometer, Gyroscope, Compass, Ambient Light, Proximity)
The interfaces available on the i.m8x can be found here
Some interfaces are pretty straight forward to match. Like RAM, display and cameras. There are specialised connections only for this purpose. The mass storage also seams to be clear but i’m not 100% sure. Should be eMMC 5.0, of which the i.mx8m supports 2. I think one for the internal 32gb and one for the microSD slot. Sadly it does not support the newer and fast UFS interface which seams to be common in modern smartphones.
This leaves at least 3 componets which need highspeed connection, Wi-FI/BT, WWAN and the USB-C connector. As i understood the AMA from @todd-weaver the WWAN will be connected via an M.2 expension port. These support many interface from I2C over USB 2.0 and 3.0 to PCIe with 1-4 lanes. On my breve research on WWAN cards it seams most of them are using USB, the progress report 5 of @nicole.faerber also stated that the modem is using the USB interface. So i assume on of the two USB interface available will be connected to the M.2 slot. The second obviously has to go to the external USB-C port. This leaves the WiFi component. On the i.mx8m there are now only left 2 PCIe lanes and the Gbit Ethernet adapter, as SPI, UART and I2C seams to slow for WiFi but good for buttons and sensors.
So will the WiFi be connected via PCIe and will it be soldered on the board?
And what happens to the second PCIe lane?
I would like to see it either exposed to the M.2 slot for replacement with small upcoming SSDs like this one or to expose it to the USB-C port for thunderbolt support. Thought i’m not sure if thunderbolt with just one PCIe lane is legit.
Am I missing something? I would like to know what is planed. Maybe you already have a draft for the schematics? I would love to see a blog post on that.