
580 THE x86 MICROPROCESSORS
Modern PC systems do not use the Motorola chip anymore – instead, they incorporate the
functions of this chip into the motherboard chipset (South Bridge) or Super I/O chip, or they
use a special battery and NVRAM module. Because of the low power capability of CMOS,
the battery life lasts up to ten years. e memory and
real-time clock are generally powered by a
CR2032 lithium coin cell (See Fig 17.1).
Many newer systems have CMOS RAM with 2KB to 4KB capacity or more. e extra
room is used to store the Plug and Play information detailing the confi guration of adapter cards
and other options in the system. As such,