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- --------------------------------------
- AMPRO COMPUTERS, INC. APPLICATION NOTE
- --------------------------------------
-
- Number: #AAN-8802 Date: Jan 19, 1988 Author: R. Lehrbaum
-
- Title: An Introduction to the AMPRO Little Boards
-
- Product(s): Little Board/PC, Little Board/186, Little Board/Z80
-
- Abstract: An overview of the AMPRO Little Board architecture, including a
- brief description of each Little Board single board computer, and
- a comparison among the various Little Boards.
- -------------------------------------------------------------------------------
-
- WHAT IS A LITTLE BOARD?
- -----------------------
- AMPRO has created the "Little Board" (TM) family of single board computers
- (SBCs) to provide engineers with an alternative to backplane based
- microcomputer board products. Each Little Board SBC incorporates all of the
- components of a complete microcomputer system on a single compact circuit
- assembly. A Little Board can often replace four or five ordinary
- microcomputer boards in a backplane architecture.
-
- The Little Board SBCs are ideal for embedded microcomputer applications in
- which the SBC is buried within an instrument, machine, controller, or other
- device. Some typical applications for the Little Boards are: data
- acquisition and control, portable instruments, protocol conversion, machine
- control, data logging, intelligent terminals, communications controllers,
- security systems, diskless workstations, remote data logging, network servers,
- distributed processing, and SCSI device control.
-
-
- Why Use a Little Board?
-
- AMPRO's Little Board SBC's have been designed using the most highly integrated
- IC's available in the industry. They are compact (45 sq.inches), low power (4
- to 7 watts), cost effective, and extremely reliable. In addition, each Little
- Board is supported with a rich set of BIOS and operating system software,
- targeted to commercial and industrial embedded applications.
-
- Included on each Little Board SBC is a microprocessor, bootstrap or BIOS ROM,
- system memory, and a full set of I/O interfaces (serial ports, printer port,
- and mass storage interfaces). In many applications, all the electronics
- required is located directly on the Little Board; in most other cases, a
- single additional application specific interface (e.g. an A-to-D converter) is
- added externally by the system designer.
-
- Using an AMPRO Little Board SBC instead of a set of boards plugged into a
- backplane reduces cost, saves space and power, increases overall system
- reliability, and simplifies system packaging. Employing a Little Board as a
- ready-to-use component rather than designing a custom microcomputer board
- results in a substantial saving in development costs, time, and risks.
-
-
- Industry Standard SCSI Bus
-
- Each AMPRO Little Board includes an industry standard Small Computer System
- Interface (SCSI) bus. The SCSI bus allows simple ribbon cable connection of a
- wide variety of external peripherals such as hard disk, tape, scanners,
- optical disks, RAM disks, printers, and LAN's. Also, the AMPRO "SCSI/IOP",
- can be used to connect data acquisition and control I/O cards to any Little
- Board SBC via SCSI.
-
- If the Little Board's SCSI interface is not needed for connection to standard
- SCSI devices, the board's SCSI port can be used as a simple digital I/O port.
- At least one manufacturer offers a line of low cost data acquisition and
- control interfaces (A-to-D, digital I/O, relays, opto-isolated inputs, etc.)
- which can be connected to any Little Board in this manner.
-
-
- Little Board Form Factor
-
- All Little Board SBCs match the footprint, mounting hole pattern, and power
- connections of industry standard 5-1/4" disk drives. This form factor (5.75"
- by 8") makes floppy or hard disk-based system integration easy and efficient,
- since the dimensions of the SBCs and mass storage devices match.
-
-
- CHOOSING THE RIGHT LITTLE BOARD FOR THE JOB
- -------------------------------------------
- The three AMPRO Little Boards -- Little Board/PC, Little Board/186, and Little
- Board/Z80 -- offer a range of processing power, onboard memory, standard I/O
- interface resources, and expansion capabilities. Table 1 summarizes the
- features of all three Little Board SBCs. The two-board set consisting of the
- Little Board/186 and Expansion/186 multi-function daughter card is also
- included. The following paragraphs summarize some of the unique features and
- advantages of each of the three AMPRO Little Board SBCs.
-
-
- Little Board/PC
-
- The Little Board/PC is a highly expandable and flexible SBC which combines the
- advantages of CMOS, small size, high integration of functionality, and IBM PC
- compatibility on a single compact board. The Little Board/PC is essentially a
- complete "Turbo" PC/XT on a single 5.75 x 8" pc board. Its performance, is
- half way between a standard IBM PC/XT and PC-AT.
-
- The Little Board/PC can be substituted for an IBM PC in virtually any
- application. Its onboard hardware and ROM-BIOS are PC compatible, and PC-DOS
- (version 3.x) is normally used as the board's operating system. In addition,
- the Little Board/PC is easily expanded via standard off-the-shelf IBM PC add-
- on cards, since a standard PC expansion bus header is included on the board.
- The AMPRO StackPlane/PC expansion adapter even allows IBM PC expansion boards
- to be integrated directly into the Little Board form factor!
-
- The IBM PC has found its way into a seemingly limitless number of industrial
- and commercial applications. All of these -- including office, factory, and
- consumer applications -- are equally well suited to implementation on the
- Little Board/PC. The AMPRO Solid State Disk (SSD) support utilities make it
- easy to convert a system from floppy-based to EPROM-based or nonvolatile RAM-
- based operation (using onboard devices). This onboard SSD support greatly
- enhances the Little Board/PC's suitability for embedded and dedicated
- applications.
-
- Summary: The main advantages of the Little Board/PC are its IBM PC
- compatibility (hardware and software), its low power consumption, its very
- high level of integration, its PC expansion bus, and its onboard solid state
- disk drive option. Because of the board's IBM PC hardware and software
- compatibility, you can develop and debug your application's hardware and
- software on an IBM PC or AT, for operation on the Little Board/PC.
-
-
- Little Board/186
-
- The Little Board/186 was designed to offer the lowest possible component count
- MS-DOS (PC-DOS) SBC. Both the 8 MHz and 16 MHz versions of the board provide
- exceptional performance/cost ratios. (The Little Board/186 provides execution
- speeds comparable to that of a PC-AT.) In addition to the board's onboard
- resources, a number of expansion options are available from AMPRO and others:
-
- o The board's SCSI bus interface can be used in a variety of ways: with
- standard SCSI peripherals, as a digital I/O bus, or with several vendors'
- low cost data acquisition and control adapters.
-
- o The AMPRO Expansion/186 multi-function daughter board offers the options
- of: 512K additional RAM, 2 serial ports, a battery backed clock, an I/O
- bus, and an 8087 math coprocessor (8087 option not available with the 16
- MHz Little Board/186).
-
- o The AMPRO Project Board/186 daughter board offers a convenient means to
- add custom circuitry or interfaces using wire-wrap.
-
- o AMPRO's implementation of the Digital Research CDOS operating system for
- the Little Board/186 (and Expansion/186) offers multi-tasking and multi-
- user support (supports four physical, and twelve virtual consoles), and
- allows direct access to hard disk partitions as large as 512 Megabytes!
-
- IBM PC-DOS (version 3.x) is normally used as the Little Board/186's operating
- system, and the board implements the standard 360K or 720K byte floppy
- formats. However, unlike the Little Board/PC, the Little Board/186 is not
- hardware-compatible with the IBM PC. (For example, the video and keyboard
- functions are routed to one of the board's RS232C serial ports rather than to
- the normal PC hardware.) Consequently, software that attempts to access IBM
- PC hardware directly cannot be used without modification. This is not a
- problem if you are writing the software yourself, since the board's ROM-BIOS
- provides a measure of compatibility with the PC environment on a BIOS level
- and supports the required PC-DOS (MS-DOS) functions. This issue is discussed
- in detail in the board's technical manual.
-
- Summary: The main advantages of the Little Board/186 are its excellent
- performance/price ratio and its use of standard IBM PC-DOS (version 3.x) as
- its operating system. The combination of the Little Board/186 and
- Expansion/186 provides many of the most commonly required system functions in
- a compact two-board package. Because the board provides a subset of IBM PC
- ROM-BIOS functions and uses PC-DOS as its operating system, you can develop
- and debug your application's software on an IBM PC or AT, for operation on the
- Little Board/186.
-
-
- Little Board/Z80
-
- The Little Board/Z80 was designed to offer the world's simplest complete CP/M
- based system. It is architecturally similar to the Little Board/186, but with
- less CPU "horsepower", less RAM and EPROM space, and no DMA. Several
- expansion options are available from AMPRO and others:
-
- o The board's SCSI bus interface can be used in a variety of ways: with
- standard SCSI peripherals, as a digital I/O bus, or with several vendors'
- low cost data acquisition and control adapters.
-
- o The AMPRO Project Board/Z80 daughter board offers a convenient means to
- add custom circuitry or interfaces using wire-wrap.
-
- Summary: The main advantage of the Little Board/Z80 is its low cost. The
- Little Board/Z80 is ideal for applications which are not time-critical, and
- which can be accomplished with the board's I/O interfaces and expansion
- options. It comes complete with an enhanced CP/M operating system as well as
- a rich set of utility software, including SCSI hard disk utilities. One
- useful utility included with the board allows it to read and write IBM PC
- diskettes. The Little Board/Z80 is also very low in component count, which
- results in high system reliability.
-
-
- Table 1. Comparison of AMPRO Little Board Features
- ----------------------------------------------------------------
- Little Board/PC
- ----------------------------------------------------------------
- CPU NEC V40
- System clock rate 7.16 MHz
- Memory data path 8 bits
- Math coprocessor no
- DMA yes
- Battery backed clock plug-in module
- Onboard RAM 256K/512K/768K
- BIOS/bootstrap EPROM 1 64K socket
- Spare memory sockets 2 (Note 1)
- Serial ports 2
- Parallel printer port yes
- No. of floppy drives 2
- Type of floppy drives 360K,720K,1.2M,1.4M
- SCSI bus interface yes
- Keyboard port yes
- Speaker port yes
- Video controller plug-in option
- Expansion bus onboard PC BUS
- Operating system PC-DOS 3.x
- Software usable IBM PC compatable
- Power consumption (typ) 4-5 watts
- Performance (Norton SI) 2.5
- ----------------------------------------------------------------
- Little Board/186 Little Board/186
- + Expansion/186
- ----------------------------------------------------------------
- CPU Intel 80186 Intel 80186
- System clock rate 8/16 MHz 8/16 MHz
- Memory data path 16 bits 16 bits
- Math coprocessor yes (8MHz only) no
- DMA yes yes
- Battery backed clock onboard option plug-in module
- Onboard RAM 1 megabyte 512K
- BIOS/bootstrap EPROM 2 64K sockets 2 64K sockets
- Spare memory sockets no no
- Serial ports 4 (Note 2) 2
- Parallel printer port yes yes
- No. of floppy drives 4 4
- Type of floppy drives 360K,720K 360K,720K
- SCSI bus interface yes yes
- Keyboard port no (Note 3) no (Note 3)
- Speaker port no no
- Video controller no (Note 3) no (Note 3)
- Expansion bus proprietary bus via SCSI (Note 4)
- Operating system PC-DOS 3.x, CDOS PC-DOS 3.x, CDOS
- Software usable MS-DOS "generic" MS-DOS "generic"
- Power consumption (typ) 7-10 watts 7 watts
- Performance (Norton SI) 4.2/8.4 (8/16MHz) 4.2/8.4 (8/16MHz)
- ----------------------------------------------------------------
- Little Board/Z80
- ----------------------------------------------------------------
- CPU Zilog Z80A
- System clock rate 4 MHz
- Memory data path 8 bits
- Math coprocessor no
- DMA no
- Battery backed clock plug-in module
- Onboard RAM 64K
- BIOS/bootstrap EPROM 1 32K socket
- Spare memory sockets no
- Serial ports 2
- Parallel printer port yes
- No. of floppy drives 4
- Type of floppy drives 360K,720K
- SCSI bus interface yes
- Keyboard port no (Note 3)
- Speaker port no
- Video controller no (Note 3)
- Expansion bus via SCSI (Note 4)
- Operating system CP/M, Z-System
- Software usable Any CP/M program
- Power consumption (typ) 5 watts
- Performance (Norton SI) ---
- ----------------------------------------------------------------
- Notes:
- (1) The LB/PC has two spare byte-wide memory sockets which
- can be used as "solid state disk drives", with
- capacities of up to 128K bytes EPROM or 512K bytes
- NOVRAM storage each.
- (2) Two of the four serial ports of the LB/186-EXP/186
- board set support both synchronous and asynchronous
- protocols, and can be jumpered for either RS232C or
- RS422 signal levels.
- (3) The keyboard and video display functions are normally
- supplied by an RS232 ASCII terminal on one of the
- board's serial ports.
- (4) The SCSI interface can be used to connect data
- acquisition & control interfaces if it is not required
- as a SCSI device interface.
- ----------------------------------------------------------------
-
-
-
- -------------------------------------------------------------------------------
- Trademarks and registered trademarks: IBM, PC/XT, PC-AT: International
- Business Machines Corporation; CP/M, Concurrent: Digital Research
- Incorporated; Z80, Zilog; Little Board, Little Board/Z80, Little Board/186,
- Little Board/PC, StackPlane: AMPRO Computers Incorporated.
- -------------------------------------------------------------------------------
- Copyright 1987, AMPRO Computers Inc. -- All rights reserved.
- -------------------------------------------------------------------------------
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-