Sun Microsystems 220R service manual SuperIO, Power Supply, Risc

C.1.12.6 RISC

The reset, interrupt, scan, and clock (RISC) ASIC implements four functions: reset, interrupt, scan, and clock. Generation and stretching of the reset pulse is performed in this ASIC. Interrupt logic concentrates 42 different interrupt sources into a 6-bit code, which communicates with the U2P ASIC. It also integrates a JTAG controller.

Highlights of the RISC ASIC features include:

Determines system clock frequency

Controls reset generation

Performs PCI bus and miscellaneous interrupt concentration for U2P

Controls flash PROM programming, frequency margining, and lab console operation

433-MHz operation

3.3-VDC and 5-VDC supply voltage

C.1.13 SuperIO

The SuperIO is a commercial, off-the-shelf component that controls the keyboard, diskette, and parallel port interfaces. It contains a DMA-driven diskette controller, two serial port controllers, an IEEE 1284 parallel port interface, and an IDE disk interface (not currently used). The SuperIO drives the various ports directly with some EMI filtering on the keyboard and parallel port signals. Support for mixed voltage modes and power management features for low power operation are also included. Features of the SuperIO include:

Two independent serial ports used for keyboard and mouse

4N82077 diskette drive interface IEEE 1284 parallel port interface

C.1.14 Power Supply

The system unit uses a 380-watt power supply that operates under the voltage range of 90 to 264 volts root-mean-square (Vrms) and a frequency range of 47 to 63 Hz. The maximum input current is 6.3.

The power supply continues to regulate all outputs for 20 milliseconds after AC power is removed.

274 Sun Enterprise 220R Server Service Manual ♦ January 2000, Revision A