Processeur Intel 8086

The first microprocessor in the Intel 80x86 family, released in 1978. It laid the foundation for the architecture of most PCs, workstations, and servers.

The 8086 uses 16-bit registers and has a 16-bit external data bus.

The 8086 can address 1 MB of memory using its 20-bit address bus.

The 8086 contains approximately 29,000 transistors.

These pins provide power to the processor. Vcc is positive voltage, and GND is ground.

Used for both data and address signals. When ALE (Address Latch Enable) is high, the bus carries addresses; when ALE is low, it carries data.

Multiplexed bus carrying addresses and status signals. S6 is for addresses, while S3 controls specific modes and operations.

Determines whether the address is for memory (M = 1) or input/output (M = 0).

This signal indicates the CPU wants to read data from memory or a device.

This signal indicates the CPU wants to write data to memory or a device.

This signal separates the address and data signals on the AD bus.

Indicates the direction of data transfer. DT/R = 1 means data is being transmitted, while DT/R = 0 means data is being received.

This signal enables the data bus for data transfer. When DEN is active, data can flow on the AD bus.

This signal provides the timing mechanism for the CPU's operation.

This signal triggers the CPU to handle a regular interrupt.

This signal triggers a high-priority, non-maskable interrupt.

This signal confirms the CPU's acceptance of an interrupt.

This signal synchronizes the CPU with slower memory and peripheral devices.

This signal resets the CPU to its initial state.

Used to put the CPU in a wait state, pending an external event.

Indicates the CPU's operating mode. Minimum mode gives more control to the system bus controller, while maximum mode gives more control to the CPU.

This signal requests access to the system bus.

This signal indicates the CPU has granted access to the system bus.

This signal enables the upper byte of the data bus, allowing the CPU to read the upper half of a 16-bit word.

These status signals provide information about the current operation being performed on the bus, indicating the state of the CPU.

This unit is responsible for processing instructions and data. It contains the arithmetic and logic unit, general-purpose registers, and the instruction decoder.

This unit fetches instructions from memory and places them in a queue for the EU to process.

These registers are used to manipulate data, pass parameters to functions, and hold results.

These registers store offsets for memory addresses, allowing the CPU to access data at specific locations in memory.

These registers store the starting addresses of segments in memory, defining the boundaries of various areas, such as code, data, and the stack.

This register contains bits that act as flags, providing information about the status of certain conditions or operations.

This register is used for general arithmetic operations, input/output operations, and the accumulation of results.

This register is used as a base register for accessing data located in a segment other than the current code segment (usually DS).

This register acts as a counter, used for loop instructions, tracking iterations.

This register is used in multiplication, division, and as an extension of the AX register. It often holds intermediate results.

This register points to the beginning of the code segment that contains the instructions of the program.

This register points to the beginning of the data segment, which contains the variables and data used by the program.

This register points to the stack segment, where the program's call stack resides.

This register points to an extra segment, used by certain block copy instructions. It provides an extra segment that the program can use.

This register, combined with the BX register, allows for indexing within the data segment. It is used for referencing data in the DS segment.

This index register, along with the BX register, is used for indexing during data transfers. It's used for referencing when data is being moved.

This register points to data on the stack, used for accessing local variables and parameters within a function.

This register points to the top of the stack, indicating the last element added to the stack.

This register, combined with the CS segment register, points to the next instruction to be executed.

The 8086 can access a total of 1 MB of memory, which is 2^20 bytes.

Address registers are 16 bits in size, allowing them to directly address 64 KB ( 2^16 bytes ) of memory.