add: Info about FACET

docs/NAVIGATION.md

@@ -20,6 +20,7 @@
   - [CPU](hardware/cpu.md)
   - [Southbridge](hardware/southbridge.md)
   - [eMMC / Flash](hardware/emmc-flash.md)
+  - [Facet](hardware/facet.md)
   - [Wifi](hardware/wifi.md)
   - [Ethernet](hardware/ethernet.md)
   - [Optical Disc Drive](hardware/optical-disc-drive.md)

docs/hardware/facet.md

@@ -0,0 +1,75 @@
+# Facet
+
+The FACET port is a universal debugging port on all models of the xbox one/series-family.
+
+Features:
+
+- SPI / eMMC
+- I2C
+- Kernel Debugging
+- Southbridge JTAG
+
+A special development board is used to interact with this port.
+Some early development kits have the FACET circuitry on-board and feature a female USB-B port for connecting directly to a PC.
+
+## Connector
+
+Label: J4E1 (Xbox One PHAT)
+
+Connector: IDC 2x13P 2.00mm
+
+Pinout
+
+- SPI -> eMMC
+- SB_JTAG -> Southbridge JTAG
+- SMC_DBG -> SMC SWO Debug
+- KER_DBG -> Kernel Debugging
+- SMBUS -> I2C
+
+| Pin | Description      | Description | Pin |
+| --- | ---------------- | ----------- | --- |
+| 1   | SMC_RST_N        | GND         | 2   |
+| 3   | SPI_MISO         | SPI_MOSI    | 4   |
+| 5   | SPI_SS_N         | GND         | 6   |
+| 7   | SPI_CLK          | GND         | 8   |
+| 9   | SB_JTAG_TDI      | SB_JTAG_TDO | 10  |
+| 11  | SB_JTAG_TMS      | GND         | 12  |
+| 13  | SB_JTAG_TCK      | 3,3V STBY   | 14  |
+| 15  | SMC_DBG_LED0_SWO | KER_DBG_CTS | 16  |
+| 17  | KER_DBG_TXD      | KER_DBG_RTS | 18  |
+| 19  | KER_DBG_RXD      | SMC_CTS     | 20  |
+| 21  | SMC_TXD          | SMC_RTS     | 22  |
+| 23  | SMC_RXD          | 3,3V STBY   | 24  |
+| 25  | SMBUS_CLK        | SMBUS_DATA  | 26  |
+
+![FACET Connector unpopulated](../_files/facet/facet_conn.png)
+![FACET Connector populated](../_files/facet/facet_conn_populated.png)
+
+## External PCB
+
+Model: FACET2 FAB A
+
+Part #: X877922-001
+
+Parts:
+
+- FTDI FT4232
+- EEPROM
+- 4x 7-segment displays
+- 7-Segment LED controller IC (I2C address 0x38)
+- External SPI Device connector
+- External JTAG Programmer connector
+- Status LEDs
+
+![FACET2 PCB Front](../_files/facet/facet2_pcb_front.png)
+
+![FACET2 PCB Back](../_files/facet/facet2_pcb_back.png)
+
+![FACET2 connected to XDK](../_files/facet/facet2_xdk_connected.png)
+
+## Software
+
+The DLL `dsmcdll.dll` is used to talk to the FACET-hardware.
+## References
+
+FACET2 PCB & smcdll.dll: [AssemblerGames archive](https://assemblergames.org/viewtopic.php?t=60058)