The Fairphone uses the Qualcomm Snapdragon 632 Mobile Platform. Not much documentation is available to the public, the best available from the vendor is a product brief. According to Wikipedia, these are "pin and software compatible with 625, 626 and 450". A few more details can be found about the older Snapdragon 626. Wikichip has a few more details
Alongside a Samsung multi chip package (MCP) lovingly named KMRH60014A-B614, providing 4 GiB of LP3DDR volatile memory combined with 64 GiB NAND with an eMMC 5.1 interface.
The following are measures and probes done against an unpowered, turned off but battery plugged, or a powered device. Running without any display or other peripherals.
The labels are arbitrarily assigned, just as a reference. Measures and reasoning or net assignment are educated guesses, at the very best. Do not rely on any of this data.
EDIT : some values has been tested, they will be in bold, ~ means reading from AC
| label | connected to | bat plugged | power on | comment |
|---|---|---|---|---|
| A | BAT 4 / GND | 0V | 0V | GND |
| B | BAT 4 / GND | 0V | 0V | GND |
| C | 0V | |||
| D | 0V | |||
| E | 0V | |||
| F | BTN 4 | 1.8V | 0V | power button |
| G | BAT 1 | 4.18V | 4.2V | |
| H | BAT 1 | 4.18V | 4.2V | |
| I | 0.2V~ | 1.32 - 1.36V | (takes a few seconds to rise after power on) | |
| K | 0.1V~ | 0V | EDL | |
| L | 0V | 1.8V | EDL | |
| N | FP 4 | 0.1V~ | ||
| O | FP 9 | 0.1V~ | ||
| P | FP 3 | 0.1V~ | ||
| Q | FP 2 | 0.1V~ | ||
| BTN 1 | 0V | 0V | volume up button | |
| BTN 2 | 0V | 0V | volume down button | |
| BTN 3 | 0V | 0V | GND | |
| BTN 4 | 1.8V | 1.8V | power button |
Notes on buttons :
- volume up button (on the case) shorts BTN 1 and BTN 3
- volume up button (on the case) shorts BTN 2 and BTN 3
- power button (on the case) shorts BTN 4 and BTN 3
| label | connected to | bat plugged | power on | comment |
|---|---|---|---|---|
| R | 0V | 0V | GND | |
| S | 0.1V~ | 0V | UART RX (?) | |
| T | 0.1V~ | 1.8V | UART TX | |
| W | 0V | 0V | GND |
Other Android devices that use the same Qualcomm platform (non of which has a LineageOS port so far, it seems):
- Asus Zenfone Max M2 ZB633KL
- Honor 8C
- Zeizu Note 8
- Motorola Moto G7
- Motorola Moto G7 Play
- Motorola Moto G7 Power
- Xiaomi Redmi 7
- Xiaomi Redmi Note 4
- Lenovo K10 Plus
The iFixIt teardown provided lots of details about the internals and served as a good starting point.