G-95-149-H-9550通用電氣模塊，GE使用配置手冊
當(dāng)裝置連接到不同的電氣設(shè)備時插座，接地電位可能有幾伏的差異。
如果每個設(shè)備的針腳1通過電纜相互連接，可能會產(chǎn)生幾安培的電流。這種情況可能不會僅對典型電纜中的小導(dǎo)線有危險，但可能還會產(chǎn)生電噪聲，導(dǎo)致數(shù)據(jù)傳輸錯誤。
這就是為什么圖E-1沒有顯示針1的連接。通常情況下，針腳7只應(yīng)連接到機箱一點接地；如果多個端子與一個端子一起使用計算機，這一點的邏輯位置是在計算機上。
G-95-149-H-9550通用電氣模塊這個端子之間不應(yīng)存在邏輯接地連接返回和機箱。介紹本章介紹MVME197LE的板級硬件功能單板計算機。本章包括董事會層面的概述和本簡介中列出的功能，然后是更詳細的硬件功能描述。前面板開關(guān)和指示燈包括在詳細的硬件功能描述。本章以一些通用內(nèi)存映射。MVME197LE模塊中的所有可編程寄存器位于ASIC中（特定于應(yīng)用的集成電路）MVME197LE、MVME197DP和MVME197SP單板計算機程序員參考指南。概述MVME197LE模塊是基于MC88110 RISC微處理器。MVME197LE具有32/64MB的DRAM，1MB閃存，8KB靜態(tài)RAM（帶備用電池），每天一次時鐘（帶備用電池）、以太網(wǎng)收發(fā)器接口、四個串行端口帶EIA-232-D接口，六個滴答定時器，一個看門狗定時器，128KB啟動ROM，一個帶有DMA（直接內(nèi)存訪問）的SCSI總線接口，一個Centronics打印機端口，A16/A24/A32/D8/D16/D32 VMEbus主/從接口和VMEbus系統(tǒng)控制器。輸入/輸出（I/O）信號通過MVME197LE的背板布線接頭P2。P2適配器板或LCP2適配器板路由信號并從連接器P2接地至MVME712系列過渡模塊。這個MVME197LE支持MVME712M、MVME712A、MVME712AM和MVME712B過渡板（此處稱為MVME712X，除非單獨規(guī)定）。MVME197LE還支持MVME712-12和MVME712-13（除非另有規(guī)定，否則稱為MVME712-XX）。這些轉(zhuǎn)換板提供配置頭、串行端口驅(qū)動程序和輸入/輸出設(shè)備的行業(yè)標準連接器。MVME197LE模塊有八個ASIC（如下所述順序：總線開關(guān)、DCAM、ECDM、PCC2和VME2）。
The problem is that when units are connected to different electrical
outlets, there may be several volts of difference in ground potential.
If pin 1 of each device is interconnected with the others via cable,
several amperes of current could result. This condition may not
only be dangerous for the small wires in a typical cable, but may
also produce electrical noise that causes errors in data transmission.
That is why Figure E-1 shows no connection for pin 1.
Normally, pin 7 should only be connected to the CHASSIS
GROUND at one point; if several terminals are used with one
computer, the logical place for that point is at the computer. The
terminals should not have a connection between the logic ground
return and the chassis.Introduction
This chapter describes the board level hardware features of the MVME197LE
Single Board Computer. The chapter is organized with a board level overview
and features listed in this introduction, followed by a more detailed hardware
functional description. Front panel switches and indicators are included in the
detailed hardware functional description. This chapter closes with some
general memory maps.
All programmable registers in the MVME197LE module reside in ASICs
(Application-Specific Integrated Circuits) that are covered in the
MVME197LE, MVME197DP, and MVME197SP Single Board Computers
Programmer’s Reference Guide.
Overview
The MVME197LE module is a double-high VMEmodule based on the
MC88110 RISC microprocessor. The MVME197LE has 32/64MB of DRAM,
1MB of flash memory, 8KB of static RAM (with battery backup), a time of day
clock (with battery backup), an Ethernet transceiver interface, four serial ports
with EIA-232-D interface, six tick timers, a watchdog timer, 128KB of BOOT
ROM, a SCSI bus interface with DMA (Direct Memory Access), a Centronics
printer port, an A16/A24/A32/D8/D16/D32 VMEbus master/slave
interface, and a VMEbus system controller.
Input/Output (I/O) signals are routed through the MVME197LE’s backplane
connector P2. A P2 Adapter Board or LCP2 Adapter board routes the signals
and grounds from connector P2 to an MVME712 series transition module. The
MVME197LE supports the MVME712M, MVME712A, MVME712AM, and
MVME712B transition boards (referred to here as the MVME712X, unless
separately specified). The MVME197LE also supports the MVME712-12 and
MVME712-13 (referred to as the MVME712-XX, unless separately specified).
These transition boards provide configuration headers, serial port drivers, and
industry standard connectors for the I/O devices.
The MVME197LE modules have eight ASICs (described in the following
order: BusSwitch, DCAM, ECDM, PCC2, and VME2).
