Intel® Desktop Board DG41RQ Technical Product Specification

Product Description1.8 Real-Time Clock SubsystemA coin-cell battery (CR2032) powers the real-time clock and CMOS memory. Whenthe computer is not plugged into a wall socket, the battery has an estimated life ofthree years. When the computer is plugged in, the standby current from the powersupply extends the life of the battery. The clock is accurate to ± 13 minutes/year at25 ºC with 3.3 VSB applied. NOTEIf the battery and AC power fail, custom defaults, if previously saved, will be loadedinto CMOS RAM at power-on.When the voltage drops below a certain level, the BIOS Setup program settings storedin CMOS RAM (for example, the date and time) might not be accurate. Replace thebattery with an equivalent one. Figure 1 on page 11 shows the location of the battery.1.9 Legacy I/O ControllerThe I/O controller provides the following features:• One serial port header• Serial IRQ interface compatible with serialized IRQ support for PCI systems• PS/2-style mouse and keyboard interfaces• One parallel port header• Intelligent power management, including a programmable wake-up event interface• PCI power management supportThe BIOS Setup program provides configuration options for the I/O controller.1.9.1 Serial Port InterfaceThe serial port header is located on the component side of the board. The serial portsupports data transfers at speeds up to 115.2 kbits/sec with BIOS support.For information aboutRefer toThe location of the serial port header Figure 10, page 44The serial port header signal mapping Table 12, page 4623