AT&T PC 6300 - Page 35

n
n
n
n
n
n
n
ft
SYSTEM OVERVIEW
ft
n
n
n
n
n
The Motherboard can be divided into four different sections with
each section providing specific functions:
• Central Processing Unit (CPU) and Direct Memory Access
(DMA)
• Memory — Random Access Memory (RAM) and
Programmable Read-Only Memory (PROM)
• Input/Output (I/O) Peripheral Interfaces
• Input/Output Connectors.
These sections are connected by three system buses:
P A Bus Carries address information generated by the CPU or
i DMA controller.
D Bus Carries data information between the CPU, DMA
controller, memory, and the I/O peripheral interfaces.
n
C Bus Carries all the control signals.
n The Motherboard uses an Intel 8288 (or equivalent) Bus Controller
to manage the various buses. It decodes the status output of the
CPU to generate the bus command and control signals at the
appropriate times. Figure 2-5 is a functional block diagram of the
Motherboard.
2-11