SKU: ZX-286/20
ZX-286/20 & ZX-286/20-8
Central Processing Unit
In Real Mode, the 80286 emulates the 8086 while executing 8086 software up to five times faster. In Protected Virtual Address Mode (PVAM) the 80286 CPU provides on-chip memory management, protection and virtual memory addressing of up to 1 gigabyte per task. The 80287 clock rate is fixed at 10MHz.
Cache Memory
Zero wait state cache memory is optional. 32K or 64K cache is available.
LBX/HSI P2 Interface
The ZX-286/20 supports memory expansion to 16MB synchronously through the LBX. The P2 interface can be configured for either the LBX or the high speed sync interface (HSI).
Dual-Port Memory
The ZX-286/20 supports jumper selectable DRAM sizes from 1 to 8 MB, as well as a size-selectable Multibus window to allow off-board memory access. The ZX-286/20-8 includes 8MB of memory attached via a daughter memory module.
Serial I/O
The ZX-286/20 utilizes the Intel 8274 Multi-Protocol Serial Controller (MPSC), a two channel serial communications interface. Software selectable baud rate generators in the 8254 timers provide the MPSC with all common communication frequencies. The protocol (i.e. asynchronous, bisync, or SDLC/ HDLC), data format, control character format, parity and baud rate are all under program control.
Programmable Timers
The ZX-286/20 provides three independent, fully programmable, 16-bit interval timers/event counters using the Intel 8254 programmable interval timer. Two of these timers/counters are available to the systems designer to generate accurate time intervals under software control. Routing for the outputs of these counters is jumper selectable. The outputs may be independently routed to the 8259A programmable interrupt controller or to the 8274 MPSC to count external events or provide baud rate generation. The third interval timer in the 8254 is dedicated to providing a clock for the programmable baud rate generator in the ZX-286/20 MPSC. The systems software configures each timer independently to select the desired function. The contents of each counter may be read at any time during system operation.
Interrupt Control
Incoming interrupts are handled by two on-board 8259A programmable interrupt controllers (PIC) and by the 80286's NMI line. Interrupts originating from up to 15 sources are prioritized and then sent to the CPU. The 8259 devices support both polled and vectored modes of operation. Further interrupt capability is available through bus vectored interrupts where slave 8259 interrupt controllers, resident on separate SBC boards. supply an interrupt vector to the on-board CPU.
Two SBX Expansion Connectors
Two 8-, 16-bit SBX connectors are provided allowing additional on-board I/O functions. SBX boards optimally support functions such as parallel and serial I/O, analog I/O , small mass storage device controllers (e.g. floppy disks). and other custom interfaces.
Advanced DMA Controller
For those applications which require frequent moving of large blocks of data, the user may install an Intel 82258, 4 channel, advanced DMA (ADMA) controller to further increase system performance. The ADMA controller supports DMA requests from the 8274 USART (2 channels) and the SBX interface. The ADMA can also perform data transfers over the on-board CPU bus, the Multibus (P1) interface, and the LBX/synchronous (P2) interface. With this arrangement, the device can rapidly move blocks of data between the ZX-286/20 board and other memory, controller and I/O boards installed in
the system.
Soft Reset
The soft reset feature allows the 80286 microprocessor to return to Real Address Mode operation from PVAM under software control. The system reset line (INIT) and the dual-port memory are not affected, and all I/O context is preserved.
80287 Math Co-Processor
The 80287 processor provides over 60 arithmetic, trigonometric, transcendental, logarithmic and exponential instructions. Supported data types include 16-, 32- and 64-bit integers, 32-, 64-
and 80-bit floating point, 18 digit packed BCD and 80-bit temporary. The 80287 meets the proposed IEEE P754 standard for numeric data processing and maintains compatibility with 8087- based systems.
Software
The ZX-286/20 is fully compatible with the SBC-286/ 12 and will run all software written for the Intel board, including SDM-286, RMX-286 and Xenix. To help the user configure the ZX-286/20, a jumper comparison table between the two boards is included in the ZX-286/20 user manual.
Specifications
PROCESSOR: 80286
OPTIONALCO-PROCESSOR: 80287
DRAM: 1,2,4 or 8MB
DUAL PORT: YES
PARITY: YES
EPROM: UP TO MB
SERIAL PORTS/DEVICE: 2/8274
PARALLEL PORTS/DEVICE: 1/8255 CENTRONICS
SBX CONN: 2
TIMERS DEVICE: 3/8254
SPEED: 20 Mhz
MULTIBUS: MASTER/SLAVE
ADDRESS WIDTH: 24
DATA WIDTH: 8/16
OPTIONAL DMA CHIP: 82258
INTERRUPTS/DEVICE: 16/8259 (2)
BUS VECTORED: YES
LBX: YES
PRODUCT CROSS: SBC286
POWERREQUIREMENTS: +5V@7A (TYP), +12V@50mA, -12V@50mA
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