Merge pull request #68 from xboxoneresearch/tuxuser/rf_unit_fpc_conne…

…ctor

rf-unit: FPC connector

docs/rf-unit.md

@@ -15,6 +15,7 @@ Components:
 - Wifi Antenna connector (J2)
 - FPC connector (J3)
 - Motherboard connector (J8)
+- Unpopulated (SW2)
 
 ####  General
 
@@ -24,9 +25,9 @@ Actual RF communication is happening via [Wifi module](wifi.md).
 
 Communication from the Nuvotun chip to the Southbridge is done via I2C.
 
-#### Pinout
+#### Connector (J8)
 
-Connector
+Pinout
 
 | Pin| Function        |
 |----|-----------------|
@@ -49,8 +50,28 @@ Connector
 | 17 | -               |
 | 18 | GND             |
 | 19 | GND             |
-
-#### Nuvoton Soundcorder chip
+
+#### FPC Connector (J3)
+
+Pinout
+
+| Pin | Function | ISD9160F Pin |
+| ----| ---------| -------------|
+| 1   |  Power   |            9 |
+| 2   |  Power   |            8 |
+| 3   |  -       |             -|
+| 4   |  -       |             -|
+| 5   |  -       |             -|
+| 6   |  Eject   |            7 |
+| 7   |  Eject   |            6 |
+
+Bridge the respective pins briefly to trigger action.
+
+FPC Cable / capacitive front panel buttons are directly wired to the ISD-Chip.
+
+#### Nuvoton Soundcorder chip (U4)
+
+Responsible for playing the power-on/off and eject sounds.
 
 Model: ISD9160F
 
@@ -62,6 +83,17 @@ Pinout (from the official datasheet linked above)
 
 ![ISD9160F Pinout](./rf-unit/isd9160f_pinout.png)
 
+This IC has multiple possible pin-configurations, the following are verified signals.
+
+| Pin | Function                   |
+| --- | -------------------------- |
+|   6 | Eject button (FPC - Pin 7) |
+|   7 | Eject button (FPC - Pin 6) |
+|   8 | Power button (FPC - Pin 2) |
+|   9 | Power button (FPC - Pin 1) |
+|  47 | I2C SCL (CLK)              |
+|  46 | I2C SDA (DAT)              |
+
 #### Communication
 
 The exact communication protocol is unknown so far.