User`s manual

Am486
®
Microprocessor PCI Customer Development Platform User’s Manual
2-14
The PCnet-FAS T+ device supports the industry’s Net PC specification. The PCnet-
FAST+ device also complies with Microsoft’s PC97 and PC98 requirements by
fully supporting the OnNow and ACPI power management initiatives; however,
the PCI CDP does not implement OnNow or ACPI. A customer design could
support these technologies by using an ATX-style power supply and motherboard
design.
4-Kbyte Serial EEPROM (C4)
An extra NM93C66M8 4-Kbyte serial EEPROM (part U81) is connected to the
Am79C972 Ethernet controller’s serial EEPROM interface. This provides
additional EEPROM space for storing user nonvolatile data.
The M1487 device’s CLKCTL signal (controlled via chipset register 40h) is used
to multiplex the Ethernet controller’s EEPROM chip select between the 1-Kbyte
EEPROM and the 4-Kbyte EEPROM. When CLKCTL is asserted (the default),
the Ethernet controller’s 1-Kbyte configuration EEPROM (part U54) is accessed
normally. When CLKCTL is deasserted, the Ethernet controller’s EEPROM
interface registers can be used to access the 4-Kbyte EEPROM to store or retrieve
user data. See Sheet 13 of the schematics in Appendix B.
Software for using the 4-Kbyte EEPROM is provided with the PCI CDP. See the
readme file on the diskette that came with your kit for information about available
utilities.