Intel 8086 microprocessor family

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8085
  • » 8-bit microprocessor
  • » Up to 8 MHz
  • » 64 KB RAM
  • » Single voltage
  • » On-chip peripherals
  • » 256 I/O ports
  • » 8080 object-code compatible
40-pin DIP
44-pin PLCC
8086
  • » 16-bit microprocessor
  • » 16-bit data bus
  • » Up to 10 MHz
  • » 1 MB RAM
  • » 64K I/O ports
40-pin DIP
56-pin QFP
44-pin PLCC
8088
  • » 8-bit data bus
 
Intel 8086 microprocessor is a first member of x86 family of processors. Advertised as a "source-code compatible" with Intel 8080 and Intel 8085 processors, the 8086 was not object code compatible with them. The 8086 has complete 16-bit architecture - 16-bit internal registers, 16-bit data bus, and 20-bit address bus (1 MB of physical memory). Because the processor has 16-bit index registers and memory pointers, it can effectively address only 64 KB of memory. To address memory beyond 64 KB the CPU uses segment registers - these registers specify memory locations for code, stack, data and extra data 64 KB segments. The segments can be positioned anywhere in memory, and, if necessary, user programs can change their position. This addressing method has one big advantage - it is very easy to write memory-independent code when the size of code, stack and data is smaller than 64 KB each. The complexity of the code and programming increases, sometimes significantly, when the size of stack, data and/code is larger than 64 KB. To support different variations of this awkward memory addressing scheme many 8086 compilers included 6 different memory models: tiny, small, compact, medium, large and huge. 64 KB direct addressing limitation was eliminated with the introduction of the 32-bit protected mode in Intel 80386 processor.

Intel 8086 instruction set includes a few very powerful string instructions. When these instructions are prefixed by REP (repeat) instruction, the CPU will perform block operations - move block of data, compare data blocks, set data block to certain value, etc, that is one 8086 string instruction with a REP prefix could do as much as a 4-5 instruction loop on some other processors. To be fair, the Zilog Z80 included move and search block instructions, and Motorola 68000 could execute block operations using just two instructions.

The 8086 microprocessor provides support for Intel 8087 numeric co-processor. The CPU recognizes all Floating-Point (FP) instructions. When the FP instructions reference the memory, the CPU calculates memory address and performs dummy memory read. The calculated address, and possibly read data, is captured by the FPU. After that the CPU proceeds to the next instruction, while the FPU executes the floating-point instruction. Thus, both integer and floating-point instructions can be executed concurrently.

Original Intel 8086 CPU was manufactured using HMOS technology. Later Intel introduced 80C86 and 80C86A - CHMOS versions of the CPU. These microprocessors had much lower power consumption and featured standby mode.


Die pictures:
Use the filter below to display manufacturers that have specific feature(s) incorporated:

List of 8086 manufacturers

AMD ID8086B

5 MHz
40-pin ceramic DIP
Industrial grade with burn-in screening

Picture of: AMD ID8086B

Fujitsu MBL8086-C / MBL8086 (ceramic)

5 MHz
40-pin ceramic DIP
White ceramic/silver top/gold pins

Fujitsu was the only company who manufactured 8086 and 8088 processors in white-ceramic DIP package. It seems that the company never manufactured 8086 microprocessors in different ceramic package, and switched directly from white ceramic package to plastic DIP package.

Picture of: Fujitsu MBL8086-C / MBL8086 (ceramic)

Harris IP80C86

5 MHz
40-pin plastic DIP
Low power (CMOS) version
Extended temperature range (-40°C to +85°C)

Picture of: Harris IP80C86

Intel C8086

5 MHz
40-pin ceramic DIP

Rare Intel C8086 processor in purple ceramic DIP package with side-brazed pins. 8086 processors in this package were produced for short period of time. This processor was manufactured in week 32 of 1978 - shortly after the 8086 family was introduced in June 1978.

Picture of: Intel C8086

OKI M80C86

5 MHz
40-pin plastic DIP
Low power (CMOS) version

Picture of: OKI M80C86

MHS HM8086

5 MHz
40-pin plastic DIP

Picture of: MHS HM8086

Mitsubishi M5L8086S

5 MHz
40-pin ceramic DIP
Purple ceramic/silver top/tin pins

Picture of: Mitsubishi M5L8086S

NEC D8086D-2

8 MHz
40-pin ceramic DIP

Picture of: NEC D8086D-2

Siemens SAB8086-C (T40-45)

5 MHz
40-pin ceramic DIP
Purple ceramic/gold top/tin pins

Temperature range on Siemens 8086 processors was marked separately from the part number. "T40/85" marking on the lid of this microprocessor means that the CPU operates in temperature range from -40 to 85 °C, i.e. in industrial temperature range.

Picture of: Siemens SAB8086-C (T40-45)

USSR KR1810VM86

5 MHz
40-pin plastic DIP with visible traces

Soviet clone of Intel 8086 in very unusual package. Top of the plastic DIP package has two cuts so that it's possible to see traces coming from the chip core. This 8086 CPU is manufactured by "Kvazar" plant. That plant also produced Intel MCS-51 clones in similar package.

Picture of: USSR KR1810VM86

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At a glance

Type:
16-bit microprocessor
Introduction:
1978
Technology (micron):
1.5, 3
Frequency (MHz):
4 - 10
Sockets:
CLCC44
DIP40
PLCC44
QFP56