NEC DIRECTION L - SERVICE, Руководство по обслуживанию

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Technical Information 1-9
Table 1-6 DMA Assignments
DMA Resource
00 Audio
01 Audio/Parallel port
02 Diskette drive
03 ECP parallel port/Audio
04 Reserved, cascade channel
05 Available
06 Available
07 Available
IDE Ports
The system board provides two IDE ports:
„
a fast IDE port (the primary channel)
„
a standard IDE port (the secondary channel).
Each port supports two devices for a total of four IDE devices. The system board allows
the connection of an IDE CD-ROM drive for system configuration flexibility without the
addition of a controller.
The fast IDE port features an enhanced IDE interface which supports up to 10 MB per
second 32-bit wide data transfers on the high-performance PCI local bus. (Standard IDE
supports 2 MB to 3 MB per second on the ISA bus.) The standard hard disk and Zip drive
(in some systems) are connected to the fast IDE port (primary channel) for high
performance. The CD-ROM drive is attached to the standard IDE port (secondary channel).
I/O Ports
The system board features an enhanced parallel port, two buffered high-speed serial ports,
and two Universal Serial Bus (USB) ports.
The enhanced parallel port supports Enhanced Capabilities Port (ECP) and Enhanced
Parallel Port (EPP) modes for devices that require ECP or EPP protocols. These protocols
allow high-speed bi-directional transfer over a parallel port and increase parallel port
functionality by supporting more devices.
The two buffered high-speed serial ports use a fast 16550 UART which supports transfer
rates up to 19.2 kilobytes (KB) per second. These ports allow the installation of high-speed
serial devices for faster data transfer rates.