Appendix C Functional Description C-7
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 pageC-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.
Twoasynchronous 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.