Sun Microsystems 60 EBus2 Devices, Cheerio Asic, Flash PROM/EPROM, SuperIO, Serial Controller

C.1.3.3 Cheerio ASIC

The PCI-to-EBus/Ethernet controller (Cheerio) ASIC bridges the PCI bus to the EBus, enabling communication between the PCI bus and all miscellaneous I/O functions, as well as the connection to slower on-board functions.

The Cheerio ASIC also contains the 10/100Mb Ethernet controller. For a brief description of the Cheerio ASIC, see Section C.1.15.3, “Cheerio” on page C-34.

C.1.4 EBus2 Devices

The EBus2 bus is controlled by the Cheerio ASIC, and supports several ports and devices.

C.1.4.1 Flash PROM/EPROM

Cheerio supports a 4 MB PROM address space. The Ultra 60 uses a 1 MB flash PROM.

C.1.4.2 TOD/NVRAM

The Ultra 60 uses a standard M48T59 chip containing 2k of NVRAM and a time-of- day clock and alarm.

C.1.4.3 SuperIO

The SuperIO chip implements several functions:

■Floppy drive interface.

■One IEEE 1284-compliant parallel port with ECP/EPP support.

■Two asynchronous serial ports for keyboard and mouse.

C.1.4.4 Serial Controller

The Ultra 60 uses a Siemans SAB82532 serial controller chip to implement two external serial ports. The ports operate at up to 460.8 Kbaud in asynchronous mode, and up to 384 Kbaud in synchronous mode.

Appendix C Functional Description C-7