The Xbox 360 Southbridge (XSB) is the chipset present on the Xbox 360 motherboard. It is responsible for many management tasks between the XCPU and different I/O present in the system.
The Xbox 360 Southbridge is a Ball Grid Array (BGA) soldered chip that was custom designed by Microsoft for the Xbox 360.
The XSB handles many important hardware features by acting as a SATA controller, USB controller, System Management Controller (SMC) and NAND controller. It also handles smaller devices such as the eject, bind, tilt switches and IR sensor on the console.
- XENON_FABK Schematics, Microsoft, 24 August 2005