Chapter 7 Theory Of Operation; Nlx Backplane; Overview; Circuit Description - Lexicon 960L Service Manual

Chapter 7 The o ry of Operation

NLX Backplane

This section describes the theory of operation of the 960L IO Backplane card.

Overview

The NLX PC form factor is an industry standard platform originally developed by Intel. The significant
difference between this form factor and other commodity PC form factors is that all system interconnect is
removed from the motherboard and located on a separate riser card. Since there are no cables connected
to the motherboard, it can be easily removed. The NLX backplane is a custom NLX riser card that Lexicon
developed to meet the needs of the integrated PC and its peripherals along with providing Lexicon specific
functionality not possible utilizing other standard PC form factors.
The 960L NLX backplane provides the interconnect between the PC motherboard, DSP cards on the PCI
bus, IDE hard drive, IDE CDROM drive, Floppy drive, IO backplane, and power distribution and
management functions. Communication between DSP cards and the IO cards in the system are provided
over a Lexicon proprietary control and audio interface using a second set of PCI style connectors. The
following system block diagram highlights its place within the 960L system.
NLX CPU
RS232 : Com1
32MB SDRAM
RS232 : Com2 433MHZ CELERON
NLX Edge Connector
PCI DSP
Slot3 BUS
(Bottom) Slot3
MIDI Ensoniq MIDI
Slot
0(Top)
IOCLK
LARC2

Circuit Description

This section is a page by page description of the 960L NLX Backplane card schematic.
6GB
HD
Primary IDE
Peripheral Buses
NLX Backplane
PCI Bus
DSP Bus
DSP DSP
PCI PCI
BUS BUS
Slot2 Slot1
Slot2 Slot1
Spare Slot Spare Slot
IO Backplane
Host Bus(Address/Data/Control)
Audio Bus(Octals, Clocks)
Slot 1 Slot 2
Spare AES
System Block Diagram
CRDOM 3.5" Floppy
Secondary IDE Floppy I/F
PCI DSP
Slot0 BUS
IOBUS
(Top) Slot0 Conn.
RVB #1
IOBUS
Conn.
Slot 3 Slot 4
AIN AOUT
Lexicon
IOBUS
Conn.
IOBUS
Conn.
7-1