Table of Contents
Advertisement
4.03 SYSTEM CONTROLLER OVERVIEW
The PicoPower (Cirrus Logic subsidiary) PT86C768/PT86C718 System Controller used
on the VIPer807 board is a two-chip solution packaged in 176-pin VQFP's. This chipset
contains power management features making it ideal for designing energy efficient
computer systems and high performance applications.
The System Controller was designed to support 32-bit 486 CPUs, capitalizing on the
unique features found in the SL-Enhanced series. It incorporates PicoPower's Power On
Demand™ technology, providing unsurpassed power management features (explained in
section 8).
The System Controller also includes features like a high performance DRAM Controller,
Clock and Reset Interface, a Local Bus IDE Drive Interface for high performance disk
subsystem, and integrated 82C206 functions.
The System Controller is 100% IBM PC/AT compatible. It includes three 8254
Counter/Timers, two 8237 DMA Controllers and two 8259 Interrupt Controllers.
4.03.1 DMA CONTROLLERS
The VIPer807 supports seven Direct Memory Access (DMA) channels. The parallel port's
ECP mode can be configured to use Channel 1 or 3. Channel 2 is reserved for the Floppy
controller. Channel 4 is used to cascade Channels 0 through 7 to the microprocessor.
Channel 5 is available for the SCSI interface. Note that with Plug and Play, DMA
channels for I/O devices and the SCSI interface can be modified via software per system
requirements.
TABLE 4-1: 8237 DMA Controllers
DMA 0
Available
DMA 1
Available (ECP)
DMA 2
Floppy controller
DMA 3
Available (ECP)
DMA 4
Cascade controller # 1
DMA 5
Available (SCSI)
DMA 6
Available
DMA 7
Available
Installing & Working With System Components
4-4
Advertisement
Table of Contents
