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 resetpulse 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 resetgeneration
Performs PCI bus and miscellaneous interrupt concentration for U2P
Controls flash PROM programming, frequency margining, and lab console
operation
33-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 operationare also
included. Features of the SuperIO include:
Twoindependent serial ports used for keyboard and mouse
N82077 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 20milliseconds after AC
power is removed.
274 Sun Enterprise 220R Server Service Manual ♦January 2000, Revision A