mdot2usbc_notes/README.md

This git (https://github.com/johnofleek/mdot2usbc_notes/) contains information about the M.2 module to USB C adapter board

John Thompson 20190307

What does the M.2 to USB C board (PCA) do?
It interfaces (adapts) USB C to M.2 plug in modules

Connectors

USB C

Supports

• USB 3.1 G1 and G2 up to 10 Gbps
• USB 2.0 Hi-Speed up to 480 Mbps

M.2

Based on the PCI Express M.2 standard with USB 2.0 and USB 3.0 interfaces
Connector is an M.2 KEY B

5V DC power connector J3

The power connector fitted to the board is a
MOLEX mini-SPOX 2.5mm Header, Right Angle, Shrouded, Friction Lock, 2 circuits 22-05-7025

Micro SIM

The board supports 1x micro SIM and one embedded solder down SIM (not fitted as a default)

DC power input

The board is powered from a nominal 5V DC input
There are two power source input connections to the board

1. J3 MOLEX mini-SPOX
   1.1 J3_PIN1 (+5V)
   1.2 J3_PIN2 ground (0V)
2. USB C
   2.1 VBUS (+5V)
   2.2 USB C GND (0V)

Note that the J3 and and USB C 5V signals are diode or'd so that the highest input voltage will supply the current to the boards internal DC power supply

The board has a regulator which powers the M.2 module with 3.4V

Preferred DC power source - external power - method 1

• Apply 5V DC power J3
• USB C 5V controls the power sequence to M.2 module

This is the preferred method because

1. It enables the board to control the M.2 module power down sequence - see M.2 module datasheet
2. The 5V power source current capability is not dependant on the hosts USB current capability

Non-preferred DC power input - USB C power - method 2

• No power source is connected to 5V DC power J3
• USB C 5V provides DC power and controls the power sequence to M.2 module

This is the non-preferred method because

1. The M.2 module power down sequence is uncontrolled - see M.2 module datasheet
2. The 5V power source current capability is dependant on the hosts USB current capability

M.2 module signal sequencing

The board has a microcontroller which sequences the power up and power down of the M.2 board. The current sequence with an external 5V power source and USB C hot plugged in and out - is like this

LED D6

This LED indicates the power sequence state. When the power is being applied to the module and the module is out of reset this LED

1. Flashes 3 times indicating powered from the USB C connector
2. Flashes 2 timed indicating powered from the external power connector

LED D1

This is the module ON LED - if the module is powered and is not in Airplane mode the LED is on

Board dimensions

The board is 61.5mm by 30.5mm - the following drawing is of the initial product build

Board supply

The board can be purchased from
Linkwave Technologies

Host connectivity

The git contains some information on connectivity using qmi.

There is an alternative connectivity option MBIM, this requires configuration of the EM module.

The following link is a site which covers our Raspberry pi product - but there is also some documentation describing using MBIM with the EM modules link

Note that MBIM is supported by Windows 10

3D model of the board assembly

STEP FILE here

This git

Checkin

git add .
git commit -m "first commit"
git push -u origin master

Clone

git clone https://github.com/johnofleek/mdot2usbc_notes.git