almanach mainboard

Mainboard layouts

Mainboard / PC design guides (www.pcdesguide.org)
  PC96
  PC97
  PC98
  PC99
  PC2001

A typical mainboard consists of:

Main chipset
I/O Controller (Serial, Parallel, Keyboard, USB, Floppy, ...)
  RTC chips
  port 70h/71h
  port 72h/73h additional 128byte

Dallas	Benchmarq	Odin
DS1187
DS1287			40 Byte RAM
DS1287A			40 Byte RAM + RAM Clear
DS12887	bq3287MT	OEC12C887	114 Byte RAM
DS12887A	bq3287AMT	OEC12C887A	114 Byte RAM + RAM Clear
DS12C887			Y2K

Expansion slots (RAM, Cards, COAST)
CPU socket
HW monitoring
Clock generator
Flash BIOS
  xxx denotes the capacity
  28Fxxx 12v
  29Cxxx 5v
  29LVxxx 3V Flash memory (not often seen)
  28Cxxx EEPROM (like Flash, but needs a special device - Flash works in the motherboard)
  27Cxxx EPROM, so you need UV to erase it and a programmer to rewrite it