The Titan board is a debugging board that can only be found in early Xbox 360 XeDK Internal and Beta Development Kits. It is a board that is used to debug the CPU and GPU without the use of PIX and loads 1bl.
The Titan board is driven by a Xilinx Spartan XC3S200 Field Programmable Gate Array (FPGA) with an external 50MHz clock. It uses two headers labelled J_YETI and J_GPUL to connect to the VID header (J7G2) and XCPU JTAG header (J8C1) respectively. The J_JTAG header is used to read and write to the FPGA's PROM chip labelled U_PROM.
The J_RISC_WATCH port is used in conjunction with an IBM RISCWatch processor probe in order to debug the XCPU.
A 4-switch DIP selector is used to configure the FPGA. It connects directly to 4 different GPIO pins. Their modes are not currently known.
Earlier models of the Titan board shown in behind-the-scenes videos show that the J_RISCWATCH header had pin 14 missing. This pin is labelled as KEY in the RISCWatch datasheet and is not wired on later Titan versions.
When powered on, the Titan has multiple LEDs that turn on. The Blue upper LEDs show the status of different pins from the J_GPUL header while the lower LEDs show the output/configuration status from the FPGA.
Earlier Titans that were paired with Internal 005 and 007 XeDKs did not have any LEDs present. It is not known whether this is true for all internal XeDKs.
Titans that were paired with Internal XeDKs usually had longer wires for J_YETI and J_GPUL most likely in order for the Titan to be used comfortably outside of the console when debugging on a hardware workbench. The extra length on these wires was zip-tied when installed inside of a case.
The Titan that shipped with Beta XeDK 007 kits had a firmware sticker labelled "VER 2.11".
Internal 005 XeDKs had an earlier Titan with a sticker labelled "2005.03.21 VER 00.80".
Internal 007 XeDKs had an similar earlier Titan with a sticker labelled "VER 1.7".
Can an XeDK boot without a Titan?
No. If the XeDK is a version that required a Titan (007 and lower) then it will not boot without a Titan. Later versions of the XeDK had 1bl stored in the XCPU and did not require it (although the headers may have still been present).