Little Board™/286 Technical Manual P/N: 5000281 Revision: A Ampro Computers, Incorporated 4757 Hellyer Avenue n San Jose, CA 95138 Tel (408) 360-0200 n FAX (408) 360-0220 http://www.ampro.
NOTICE DISCLAIMER Ampro Computers, Incorporated makes no representations or warranties with respect to the contents of this manual or of the associated Ampro software products, and specifically disclaims any implied warranties of merchantability or fitness for any particular purpose. Ampro shall under no circumstances be liable for incidental or consequential damages or related expenses resulting from the use of this product, even if it has been notified of the possibility of such damages.
PREFACE This manual is for integrators and programmers of systems based on the Ampro Little Board/286 single board system. It contains information on hardware requirements and interconnection, and details of how to program the system. There are four chapters, organized as follows: n Chapter 1 -- Introduction. General information pertaining to the Little Board/286, its features, and specifications. n Chapter 2 -- Hardware Configuration.
TABLE OF CONTENTS CHAPTER 1 - INTRODUCTION 1.1 General Description .............................................................................................................. 1-1 1.2 Little Board/286 Features...................................................................................................... 1-3 1.3 Little Board/286 Specifications............................................................................................. 1-4 CHAPTER 2 - HARDWARE CONFIGURATION 2.1 Introduction ........
CHAPTER 3 - SOFTWARE CONFIGURATION 3.1 Introduction ........................................................................................................................... 3-1 3.1.1 Conventions ............................................................................................................ 3-1 3.2 Operation with DOS.............................................................................................................. 3-2 3.2.1 Configuration Options ....................................
APPENDIX A - SLOT BOARD/286 UTILITIES SCSI-ID ............................................ SCSI Initiator ID reporting SCSI-VER ........................................ SCSI version reporting SCSICOMP ...................................... SCSI device block compare SCSICOPY ....................................... SCSI device block copy SCSIFMT ......................................... SCSI hard disk formatter SCSIPARK ....................................... SCSI hard disk park utility SCSITOOL .............
FIGURES AND TABLES FIGURES Figure 1-1 Mechanical Dimensions.......................................................................................... 1-5 Figure 2-1 Figure 2-2 Connector and Jumper Locations ........................................................................... 2-2 Byte-Wide Socket Jumpering ................................................................................. 2-9 Figure 4-1 Little Board/286 Block Diagram ................................................................
CHAPTER 1 INTRODUCTION 1.1 GENERAL DESCRIPTION The Little Board/286 provides system designers with a high performance, AT-compatible single board microcomputer system that requires no more space than a half height 5-1/4" disk drive. This unique single board system is functionally equivalent to a normal AT motherboard and three or four expansion cards.
Sockets on the Little Board/286 allow onboard EPROM (up to 256K bytes) or battery-backed RAM (up to 64K bytes) to function as a bootable DOS compatible Solid State Disk (SSD) drive. SSD operation offers several key advantages, including improved speed, reliability, and ruggedness, as well as reduced power consumption. Ampro's optional SSD support software converts DOS based applications into EPROM format automatically, without the need for special programming techniques.
1.2 LITTLE BOARD/286 FEATURES A Complete AT Compatible System on One Board n All the functions of a motherboard and 4 expansion cards in the space of a half-height 5-1/4" disk drive! n Runs standard IBM PC and PC/AT software, including: -- Disk Operating Systems -- Languages (C, Pascal, Fortran, Basic,...
1.
1-5 .2 3 0 .9 0 0 .8 0 0 .7 0 0 .6 0 0 0 3 .9 7 5 .1 2 5 D IA 2 PL 5 .5 2 0 5 .7 5 0 5 .5 5 0 0 2 .2 2 5 J1 0 J9 4 .4 2 5 J 11 4 .7 0 0 Figure 1 -1 . Me chanic al Dim e nsions 1 .8 0 8 .1 4 4 TYP 4 PL 4 .9 2 8 5 .2 2 5 5 .1 2 5 6 .0 0 0 J8 J7 6 .0 0 0 6 .5 0 0 J1 J6 J3 J2 7 .7 5 0 J5 J4 .1 4 4 DIA 7 .3 0 0 8 .0 0 .1 7 5 .7 0 0 1 .3 0 0 2 .0 5 0 2 .8 0 0 3 .5 0 0 4 .2 0 0 4 .6 2 5 5 .
CHAPTER 2 HARDWARE CONFIGURATION 2.1 INTRODUCTION This chapter describes what is required to integrate the Little Board/286 with a wide variety of external devices, including keyboards, printers, modems, floppy and hard disk drives, and monitors. Information is provided regarding the board's connector signals and pinouts, external device requirements, interconnection cable wiring, and board configuration.
2-2 U3 U4 1 3 5 2 4 6 W2 1 W2 0 W1 3 W1 2 W1 0 W1 1 W3 W4 W5 J 10 W2 W2 2 J9 RP6 RP5 RP4 Figure 2 -1 .
The board's I/O connectors consist of dual-row male header connectors, of varying lengths. Each of these headers can be mated with either flat ribbon (IDC) or discretely-wired connectors. J2, J3, J4, J5, and J6 have been placed together at one end of the board so that a single header plug can mate with one or more of these connectors as a group. In some applications it is preferable to plug a specialized PC board assembly onto several or all of the I/O connectors (J2-J8).
(CTRL-ALT-ESC) or through the SETUP program on the Little Board/286 Utilities diskette. Table 2-3 lists the main functions that are controlled by the contents of the nonvolatile Configuration Memory. Table 2-3.
Table 2-4. Power Connector (J1) PIN 1 2 3 4 SIGNAL NAME FUNCTION ----(not used) Ground Ground return Ground Ground return +5VDC +5VDC +/- 5% Housing: AMP 1-480424-0 Pins: AMP 60619-1 Little Board Power Connector +5V GND GND N/C J1 Cable Connector Wiring 4 3 2 1 No Connect 1 2 Little Board 3 4 GND GND +5V Figure 2-2. Power Connector Wiring The precise power requirements of the Little Board/286 depend on a number of factors, including what functions are present on the board (e.g.
2.3 ONBOARD DEVICE OPTIONS AND CONFIGURATION This section includes the configuration and installation of onboard devices and options. These include DRAM and byte-wide memory devices, nonvolatile RAM cartridges, math coprocessor, and a variety of onboard expansion MiniModules including the Ampro MiniModule video controllers. 2.3.1 CPU and Bus Half-Speed Options The speed of the CPU or of the AT Expansion Bus can be switched to one-half of the normal clock speed under software control.
Table 2-5. Onboard DRAM Memory Size Jumpering SIMM QTY. 2 4 4 2 2 2 4 SIMM TYPE 256K 256K 256K 1M 1M 1M 1M LOCATION W3 W4 W5 U1,2 U1,2,3,4 U1,2,3,4 U1,2 U1,2 U1,2 U1,2,3,4 open short open short open short open short open short short short open open short short short open open open open SYSTEM MEMORY 512K 640K 640K 512K 640K 640K 640K EXTENDED MEMORY 0K 0K 384K 0K 0K 1408K 3456K On a 12MHz system, use 120 nS (or faster) SIMMs. On a 16MHz system, use 100 nS (or faster) SIMMs.
2.3.4 Byte-Wide Memory Sockets The Little Board/286 has two onboard byte-wide memory device sockets that can accommodate a variety of EPROM and nonvolatile RAM (NOVRAM) devices, used for simple program storage or as "Solid State Disk" (SSD) drives. Some of the byte-wide devices which can be used in these sockets are shown in Table 2-6. The NOVRAM cartridges described in the table connect with a short ribbon cable (Dallas P/N DS9000) to a byte-wide socket: U32 or U33.
Using the Ampro SSD software, the byte-wide sockets can serve as individual SSD drives, or they can be combined into one larger drive. SSD drives can be used along with normal (floppy and hard disk) drives. Ampro's SSD Expansion Board provides additional SSD sockets. Byte-Wide Socket Configuration If the byte-wide memory sockets are used, they must be configured by means of jumpers for the device type in use. W12 and W13 are associated with U32, while W20 and W21 are associated with U33.
As mentioned previously, the required access time for devices plugged into U32 and U33 is 300 nS (or faster), on both 12 MHz and 16 MHz boards. Note When a byte-wide memory device is enabled, its memory address space is unavailable for use by other devices on the AT bus. A byte-wide socket must be marked as "disabled" by means of the Ampro SETUP utility before its memory space can be used for other purposes. 2.3.
Note When an EGA or VGA controller's switches or jumpers are configured for a monochrome mode, W22 should be set for "color" rather than "mono". The function of W22 is replicated on the Utility Connector (J5) pins 9 and 10. This was done to facilitate the use of an external mono/color configuration switch, if needed. Pins 9 and 10 of J5 are not normally populated with connector pins, so you must add pins in that location if you wish to take advantage of the option.
2.4 PERIPHERAL CONNECTIONS AND CONFIGURATION This section covers the interface requirements of the board's external device interface connectors. Information is provided on interface and device characteristics, connector pinouts, signal definitions, jumper configuration, and nonvolatile Configuration Memory setup. 2.4.
Power Indicator LED Two pins (5,6) of the Utility Connector provide connections for an external power indicator LED device. 15 mA of sourced current is available (+5V through 330 ohms). Pin 5 goes to the LED's cathode, and 6 to its anode. AT Bus Power Options Four pins (7,8,9,10) of the Utility Connector allow the connection of an external source of +12VDC, -5VDC, and -12VDC power to the board's AT bus (J9) for use by plug-in expansion cards. The Little Board/286 does not require these voltages.
Table 2-10. Keyboard Connector (J5) J5 PIN SIGNAL NAME 1 Keyboard Clock 2 Keyboard Data 3 (no connection) 4 Ground 5 Keyboard power 6 Keyboard inhibit 7 (*) No connect 8 (*) No connect 9 (*) Same as W22-1 10 (*) Same as W22-2 (*) = No connector pins. DIN PIN 1 2 3 4 5 --- 2.4.3 Parallel Printer Port The board's serial/parallel controller option (U22) must be installed for this function to be available.
Table 2-11.
Note There is no means to alter the printer port's interrupt, so although its I/O port address can be set to the standard LPT1 or LPT2 values, its interrupt remains at IRQ7. DOS does not use the interrupt, while some printer port control software does (such as print spoolers). Bidirectional Parallel Port Usage The parallel printer port can be used as a normal AT printer port, or it can be used for general purpose programmable I/O.
Pin 10 of each serial port connector is an enable signal which is normally left unconnected When it is brought to a TTL high level, it disables the input signals. It is pulled low on the board by a 1K ohm resistor. This signal is intended for board test purposes only. J3 is the primary serial port, and is supported by the board's ROM-BIOS as the DOS "COM1" device. The secondary serial port is J2; it is supported as the "COM2" device.
n Drive Quality -- High quality, DC servo direct drive motor floppy disk drives are recommended. n Drive Combinations -- Any combination of supported drives can be used. n Drive Select Jumpering -- Both drives must be jumpered to the second drive select. Use a floppy cable with a segment of wires "twisted" as is the usual practice in PC and AT compatible systems.
Floppy Interface Connector Table 2-16 shows the pinout and signal definitions of the board's floppy disk interface connector, J8. J8 is identical in pinout with the floppy connector of standard AT and PC floppy controller boards. Note that, as in a standard PC or AT, both floppy drives are jumpered to the same drive select -- as the "second" drive. The drives are uniquely selected as a result of a swapping of a group of seven wires (conductors 10-16) that must occur in the cable between the two drives.
2.5 SCSI INTERFACE The board's Small Computer System Interface (SCSI) controller option (U7 and associated components) must be installed for this interface to be available. The SCSI interface uses a 50-pin male header connector (J7) to interface with SCSI compatible peripherals. Table 2-17 shows the pinout and signal definitions of this interface. Refer to your SCSI device documentation, or the ANSI X3.131 SCSI specification (referenced in Chapter 4) for detailed information on the signal functions.
2.5.1 Normal Use of SCSI The board's SCSI bus interface can serve a variety of purposes, including connection of hard disk controllers, tape controllers, text scanners, and printer and communications servers. Support is provided by the board's ROM-BIOS for booting of DOS from a SCSI device such as a hard disk. Virtually any device compatible with the SCSI Common Command Set for direct access devices can be used through the ROM-BIOS support.
As its name implies, the SCSI/BIOS consists of a set of low level functions which have been incorporated into the ROM-BIOS to provide a hardware independent interface between system software and peripheral devices connected to the SCSI bus. The advantage of the Ampro SCSI/BIOS is that programmers can write software that uses devices connected to the SCSI bus without having to be concerned with the details of operating the board's SCSI bus interface.
Internally, pins 2-7 of the SIP networks have 220 ohm resistors connected to +5 volts (pin 8), and 330 ohm resistors connected to ground (pin 1). Note that the SCSI Bus termination networks consume significant power (.8 watt). If power consumption is critical, consider having the bus termination external to the board, and externally powered. External Termination Power Option The SCSI specification includes the option of using external bus termination.
2.6 AT EXPANSION BUS An AT compatible expansion bus appears at connectors J9 and J10, except that it is brought out to a pair of header connectors, rather than edgecard connectors. The PC-bus subset of the board's AT Expansion Bus connects to the first 62 pins of J9; the two additional pins of J9 (A32, B32) offer additional ground signals, for enhanced system reliability. The 36-pin edgecard connector, normally included in an AT expansion bus, is replaced by a 40pin header connector, at J10.
Several options are available for mounting multiple MiniModules on the Little Board/286: n Stacker/MM -- Allows two MiniModules to be stacked together and mounted as a single unit. n StackPlane/MM -- Provides two expansion bus header connectors for mounting MiniModules on a Little Board form-factor board. When used with the Stacker/MM, up to four MiniModules can be attached. The SSD Expansion board also offers two expansion bus header connectors for mounting MiniModules.
2.6.3 Expansion Bus Cable Considerations Here are several points regarding the use of the board's AT Expansion Bus: n Cable Length -- Keep the ribbon cable used as short as possible. Expansion bus cables in excess of six inches can result in reduced system reliability. We recommend: -- For cable lengths up to 6 inches, use a high quality ribbon cable, such as 3M part number 3365/64 (64 conductor) and 3365/40 (40 conductor).
Note that the Little Board/286 does not generate +/- 12VDC or -5VDC for the AT Expansion Bus. If devices on the AT Expansion Bus will require these voltages, they can be supplied to the AT Expansion Bus connector from the board's utility connector (J4). One handy feature of the Ampro MiniBackplane/ATBus is that it has a provision for optional onboard DC-to-DC converters for all bus voltages other than +5VDC. Table 2-18A.
Table 2-18B.
Table 2-18C.
2 . 6 . 5 Interrupt and DMA Channel Usage The PC and AT buses provide a number of interrupt and DMA control signals. When you add PC or AT bus plug-in cards which require either interrupt or DMA support, you must select which channels of these functions will be used by the added card. This is typically done using either switches or configuration jumpers on the plug-in card.
CHAPTER 3 SOFTWARE CONFIGURATION 3.1 INTRODUCTION This chapter provides an overview of the system features, configuration options, and utilities that are available under the DOS operating system. A combination of standard DOS and Amprosupplied utilities and drivers allows you to create a highly customized system based on the Little Board/286.
OPERATION WITH DOS The Little Board/286 and its ROM-BIOS have been designed to allow the use of IBM PC-DOS, Microsoft MS-DOS, or Digital Research DR-DOS, versions 2.x or 3.x, and PC-DOS or MS-DOS version 4.01, as the board's operating system. Throughout this chapter, the term "DOS" will be used to refer to any of these operating systems, except in cases where a difference in operation exists. Caution Many variations of MS-DOS exist which have been customized for operation on specific computer systems.
3.2.1 Configuration Options A wide degree of system configurability is available through options provided by: (1) the DOS operating system and its drivers and utilities; (2) the Ampro Little Board/286 Utilities.
3.2.3 Two Special Files Before reading about the various options available for customizing your system, you should understand the use of two special DOS files: CONFIG.SYS and AUTOEXEC.BAT. These are discussed in detail in the DOS reference manuals, but will now be discussed briefly as an introduction to this chapter. n CONFIG.SYS -- "CONFIG.SYS" is a text file, which you must create.
3.3 CPU AND BUS SPEED INITIALIZATION One of the most important system parameters to configure is the half-speed option for the CPU and/or expansion bus. In most installations, you will want to have the CPU operate at full speed. Assuming 12 or 16 MHz operation of the board's CPU, it is most common to operate the bus at "half-speed", due to the fact that many PC and AT bus expansion boards require a maximum bus speed of 8 MHz. There are two ways to control the half-speed options: 3.3.
3.4 USING A PARALLEL PRINTER No special configuration is required when using the system with a Centronics type parallel printer. Simply refer to the parallel printer as the DOS "LPT1" or "LPT2" device (depending on how the port is jumpered -- see note below), and be sure the parallel printer port is enabled, using SETUP. Most application software uses LPT1 as the default printer port, so printing to the parallel printer interface is automatic if the port is jumpered that way.
Note The "COMn" (n=1,2) designation is a logical value, not a physical value. During the system boot sequence, the ROMBIOS scans both sets of serial port addresses, and installs the first serial port it locates as the COM1 device, and the second, if found, as COM2. Therefore, if you disable the board's primary serial port, the secondary port will become "COM1", not "COM2"! There must be COM1 (primary serial port) device elsewhere in the system for the onboard secondary serial port to be accessed as COM2.
Note Many DOS programs use ROM-BIOS display control functions, or write directly to video RAM. Such software cannot be used on a serial console device (e.g. ASCII terminal), with the exception of programs intended to be used with the DOS ANSI.SYS driver if the terminal is ANSI compatible. On the other hand, programs which output appropriate terminal control strings to the console, or which are specifically installed for the particular serial display device, can be used.
Now you can print to the serial printer as though it is connected to the system's parallel printer port. You can return the printer device to the Parallel Printer port with the following command: A>MODE LPT1 If desired, MODE commands can be included in your system's AUTOEXEC.BAT startup file to assign the printer function to a serial port.
3.6 USING FLOPPY DRIVES DOS compatible floppy disk functions are provided within the ROM-BIOS. Diskettes may be copied, formatted, verified, etc. using the standard DOS commands. This includes all of the DOS mini (5-1/4") and micro (3-1/2") floppy formats -- 160K, 180K, 320K, 360K, 720K, 1.2M, and 1.44M -- provided the appropriate version of DOS is used (see Chapter 2). In addition, dual capacity use of high density floppy drives is supported, which means that 360K floppies can be read in a 1.
3.7 USING SCSI HARD DISK DRIVES One unique feature of the Little Board/286 is that its ROM-BIOS contains hard disk support functions, which map to the board's Small Computer System Interface, rather than to a standard AT bus hard disk controller. This has the advantage of offering the added flexibility of SCSI device support, with its benefits of interchangeability of peripherals, flexibility of configuration, and ease of system upgrading and support.
Note PC-DOS and MS-DOS allow installing one or two hard disk drives, while DR-DOS allows up to eight. n BOOT Device Specification -- the board's Configuration Memory also contains a parameter indicating whether a hard disk or floppy drive is to be used as a boot device. SETUP's "Extended Options/Peripheral Configuration" menu contains this parameter. Using this option, the boot device can be set as either the "Floppy Drive" or "Hard Drive".
The following is a brief procedure you can use to prepare a SCSI hard disk drive for use with DOS: 4. Setting the SCSI Device ID’s – using the options in SETUP’s Extended SCSI and “Hard Disk Configuration” menu, specify the appropriate SCSI device ID’s for both the drive (must match jumpers on the drive or drive controller) and the Ampro Little Board/286. Normally, you will want to set the Ampro Little Board/286 to SCSI ID 7 so that a SCSI bus Reset will be issued on system powerup or reset.
3.8 USING AT BUS CONTROLLER INTERFACED HARD DISK DRIVES The Little Board/286 can be used with one or two hard disk drives connected by means of a standard AT bus plug-in hard disk controller. These can be used instead of SCSI hard disk drives, or along with SCSI drives.
n BOOT Device Specification -- the board's Configuration Memory also contains a parameter indicating whether a hard disk or floppy drive is to be used as a boot device. SETUP's Extended Options/Peripheral Configuration menu (second menu page) contains this setting. Using this option, the boot device can be set as either the "Floppy Drive" or "DOS Hard Drive". When "DOS Hard Drive" is selected, the drive indicated by the "1st Hard Disk" in the "DOS Disk Map," defined above, becomes the boot drive.
CHAPTER 4 THEORY OF OPERATION 4.1 INTRODUCTION With the exception of several unique functions which are discussed in detail in this chapter, the Little Board/286 is functionally identical, from both a hardware and software perspective, with the IBM PC/AT computer. This chapter will only briefly touch on standard PC/AT features and functions, but rather will focus on the non-standard functions, which are unique to the Ampro Little Board/286.
4-2 1 5 C ha nne l Inte rrup t C o ntro ller 7 C han nel DMA C o ntro ller RS2 3 2 C Se rial Po rt Ba ttery Bac ke d RTC C o nfigu ration C M O S NO VRAM Para lle l Prin ter Port h F lo pp y D isk C o ntro ller O ptio n PC /AT C O M PATIBLE E XPANSION BUS C o ntro lle r Tim in g 3 C ha nne l C o nfiguratio n EE PRO M C PU 80286 SC SI C o ntro lle r Op tio n 1 2 or 1 6 M Hz 80287 Op tio n F igur e 4 -1 .
4.2 OVERALL ARCHITECTURE As mentioned previously, the Little Board/286 is essentially a complete PC/AT compatible system, including the equivalent of a motherboard and three or four expansion cards, constructed on a single electronic assembly that has the same dimensions as a AT expansion card. Figure 4-1 shows a block diagram of the Little Board/286's onboard logic.
4.2.3 System Memory Map The 80286 used as the central processing unit (CPU) on the Little Board/286 has a memory address space which is defined by 24 address bits. Therefore, it can address 16 megabytes of memory. The board's memory space is utilized as indicated in Table 4-1.
4.2.4 System I/O Map Table 4-2 provides a detailed listing of the I/O port assignments used on the Little Board/286. With the exception of the SCSI controller and configuration EEPROM access register, the I/O port functions and addresses shown in Table 4-2 are all functionally identical with their counterparts in a "standard AT" system from both a hardware and software perspective.
4.3 AT MOTHERBOARD LOGIC Among its many functions, the Little Board/286 contains the equivalent of an entire PC/AT motherboard. This section briefly describes the motherboard subsystem contained within the Little Board/286. 4.3.1 CPU A powerful 80286-type microprocessor (U5) represents the central element in the Little Board/286. A variety of equivalent devices can be used, including the Intel 80286 standard device, the AMD 80L286 low power device, and Harris (or other) 80C286 CMOS device.
The CPU and bus half-speed options are controlled by the ROM-BIOS SETUP utility and SETSPEED program, which is included on the Little Board/286 Utilities diskettes. Refer to Chapter 3 for further details. The expansion bus speed parameter in the board's Configuration Memory is set to half-speed operation at the factory. 4.3.3 ROM-BIOS Sockets A pair of EPROM sockets (U10,U11) with 16-bit wide data access normally contains the board's AT compatible ROM-BIOS.
4.3.5 Interrupt Controllers A pair of 8259A compatible interrupt controllers, within the board's ASIC devices, provides fifteen prioritized interrupt levels. Of these, several are normally associated with the board's onboard device interfaces and controllers, and several are available on the AT Expansion Bus. Table 4-3 lists the normal interrupt usage. Table 4-3.
As in all AT compatible computers, several distinctions exist between the features of DMA Channels 0-3 and Channels 5-7: n Channels 0-3 -- these four channels are similar to those of a PC, and are used for 8-bit transfers, between 8-bit I/O adapters and both 8-bit and 16-bit system memory. For these channels, addresses A0-A15 are generated directly by the 8237A compatible DMA controller logic, while addresses A16-A23 are generated by AT compatible DMA page registers.
DMA Transfer Speed The board's DMA controller operates at one-half the CPU speed. Therefore, the DMA controller clock rate is 8 MHz on 16 MHz boards, and 6 MHz on 12 MHz boards. This results in a clock cycle time of either 167 (12 MHz boards) or 125 nS (16 MHz boards). In the AT architecture, DRAM refresh is controlled over the CPU/memory bus. For this reason, all DMA data transfers are generally done using the controller's byte mode, so that the required refresh cycles can occur.
n It is used to operate the “A20 Gate” and 80286 CPU reset which are associated with system protected mode control, as on other AT compatible computers; n It provides several control signals for Little Board/286 onboard logic control, including: CPU and bus speed control; EEPROM device control; serial port enables; printer port enable; byte-wide socket enables; mono/color jumper sensing; keyboard disable switch sensing. 4.3.
grounds for optional use to enhance system reliability. An independent crystal (Y1) provides J9's 14.318 MHz bus OSC signal. The timing of the OSC signal is asynchronous to other expansion bus signals. For compatibility with standard implementations of the AT bus, four wait states are inserted in all expansion bus transactions for both I/O and memory cycles.
Because both of these critical circuits are fully digital, the floppy drive interface is highly reliable and temperature independent. The board's ROM-BIOS initializes the floppy subsystem configuration based on data stored within the board's Configuration Memory (in the battery-backed CMOS RAM within the clock device). All combinations of supported drives can be used (see Chapter 2). Interrupt channel 6 and DMA channel 2 are used for normal operation of the floppy controller subsystem.
4.5.2 Parallel Printer Port The parallel printer port on the Little Board/286 is functionally identical to that found in a standard AT with one exception: its eight data lines can be put in a mode in which they are used to read the state of the printer port data lines (rather than being write only). Because you can use this port as a two-way 8-bit bus, it can be very valuable in custom applications.
It is also possible to use the four control lines as input lines. To use a control line as an input line, you must first write to its corresponding bit in the control register. Write a 1 if the line is shown as active high in Table 4-6, Write a zero if it is shown as active low. This will cause the corresponding signal line to "float" (be in a TTL high state). The drivers for these lines are open collector drivers with 10K ohm pullups. When these lines are floating, they can be used as inputs.
4.6 SMALL COMPUTER SYSTEM INTERFACE (SCSI) The board's SCSI bus interface is completely controlled by an AIC-6250 SCSI protocol controller device. The AIC-6250 contains a complete ANSI X3.131 compatible SCSI bus interface, including 48 mA bus drivers, 8-bit data FIFO buffer, and hardware support for bus arbitration, REQ/ACK handshaking, asynchronous and synchronous SCSI data transfer modes, and all required SCSI Initiator and Target functions.
Standard Hard Disk Support Drives connected to the board's Small Computer System Interface (SCSI) can be used to replace the hard disk controller function normally found in a standard AT.
Ampro SCSI/BIOS To make it easy to use SCSI devices and functions not supported by the standard Ampro drivers and utilities, functions have been included in the board's ROM-BIOS which allow the use of the SCSI interface without the need for direct hardware programming. This support is accessed through an extension of the INT13 ROM-BIOS support, and is known as the Ampro SCSI/BIOS.
If you plan to use SCSI interface in non-SCSI applications, you will probably require a copy of the AIC-6250 SCSI Chip technical manual referred to previously in this chapter. 4.7 BYTE-WIDE MEMORY SOCKETS The two 28-pin byte-wide memory sockets at U32 and U33 support a variety of 28-pin JEDEC pinout memory devices, including EPROM, static RAM, EEPROM, page-addressed EPROM, and nonvolatile RAM (NOVRAM) cartridges.
4.8 CONFIGURATION EEPROM A great deal of flexibility of system configuration has been made possible by the inclusion of a 1,024 bit serial electrically erasable EPROM (EEPROM). The device used is contained in an 8pin IC at location U14. The configuration EEPROM is normally used in two ways: part of it is reserved for Ampro setup information; the rest of it is available for OEM data storage. The 1024 bits of the configuration EEPROM have been allocated in two groups: Ampro data area, and OEM data area.
APPENDIX A LITTLE BOARD/286 UTILITIES SOFTWARE
APPENDIX A LITTLE BOARD/286 UTILITIES SOFTWARE INTRODUCTION This Appendix contains detailed information on each of the driver and utility programs supplied on the Ampro Little Board/286 Utilities diskette. Each program's description explains what the program does, and how it is used. Program descriptions are in alphabetical order, so this chapter can serve as a handy reference. Each program is identified by a version and revision level.
