ADLINK VPX3000 - Manual (Page 29)

Functional Description 17
VPX3000
3.5 PMC/XMC Site
The VPX3000 Series supports one XMC site for rear I/O expan-
sion. The XMC site provides a x8 PCI Express 2.0 lane. Jn6 rear
XMC I/O connector is compliant to VITA 46.9, X8d+X12d.
3.6 Real Time Clock
The Intel® QM77 PCH contains a Motorola MC146818B-compati-
ble real-time clock (RTC) with 256 bytes of RAM. The real-time
clock performs two key functions: keeping track of the time of day
and storing system data. The RTC operates on a 32.768 KHz
crystal and is powered by P3V3_AUX or VBAT. There is no exter-
nal RTC battery on the VPX3000 to power the RTC after the sys-
tem is powered off.