INTEL 4004

INTROUCTION:

The Intel 4004 is a 4-bit central processing unit
(CPU) released by Intel Corporation in 1971. The 4004 is the first complete CPU on one chip, the first commercially available microprocessor, a feat made possible by the use of the new silicon gate technology allowing the integration of a higher number of transistors and a faster speed than was possible before. The 4004 employed a 10 μm silicon-gate enhancement load pMOS technology and could execute approximately 92,000 instructions per second (that is, a single instruction cycle was 11 microseconds).

SINGLE CHIP CPU:

The 4004 is a complete CPU (central processing unit) integrated in a single chip, making the 4004 the world's first microprocessor. Before the microprocessor, CPUs were built with many chips or with a few LSI (large scale integration) chips. The CPUs built with a few LSI chips were steps toward the microprocessor but were not microprocessors. The 4004 is part of a family of four LSI components - the MCS-4 family - that can be used to build digital computers with varying amounts of memory. The other components of the MCS-4 family are memories and input/output circuits, which are not considered part of a CPU in any computer classification, but are necessary to implement a complete computer.

SPECIFICATIONS:
the 4001 is a ROM (read-only memory) with 4 lines of output
the 4002 is a RAM (random access memory) with 4 lines of input/output
the 4003 is a static shift register to be used for expanding the I/O lines, for example, for keyboard scanning or for controlling a printer
Maximum clock speed is 740 kHz[4][5]
Separate program and data storage (i.e., a Harvard architecture). Contrary to most Harvard architecture designs, however, which use separate buses, the 4004, with its need to keep pin count down, uses a single multiplexed 4-bit bus for transferring:
12-bit addresses
8-bit instructions
4-bit data words
Instruction set contains 46 instructions (of which 41 are 8 bits wide and 5 are 16 bits wide)
Register set contains 16 registers of 4 bits each
Internal subroutine stack is 3 levels deep.

SOME FACTS OF 4004:

* SMALL & POWERFULL:
Revolutionary microprocessor, measuring 1/8th by 1/6th of an inch—the size of a fingernail—delivered the same computing power as the first electronic computer, the ENIAC*, built in 1946, which filled an entire room and used 18,000 vacuum tubes.

* TRANSISTOR COUNT:

Transistor countToday's Intel® Core™2 Duo processors contain over 291 million transistors. This is 100,000 times the number of transistors than were in the 4004, which had 2,300 transistors when it was introduced in 1971.

* A HUMAN HAIR:

The Intel 4004 microprocessor circuit line width was 10 microns or 10,000 nanometres. Today Intel's microprocessors have circuit line widths of .065 microns or 65 nanometers. A nanometer is one billionth of a meter. By comparison, a human hair is approximately 100 microns or 100,000 nanometers.

* MANUFACTURING:

The Intel 4004 microprocessor was produced on 2" wafers initially and then on 3" wafers. Today's microprocessors are produced on 12" or 300mm wafers. The Intel 4004 microprocessor is unique in that, if it is not the smallest, it is one of the smallest microprocessor designs that ever went into commercial production. The 4004 microprocessor is composed of 5 layers. The 4004 consists of 2,300 transistors based on 10 micron technology fitting on a 12mm2 area.
ASPECTS OF 4004:
* Program memory size is 4 KB. All conditional instructions work within currently selected ROM (256 bytes). Unconditional jump and jump to subroutine instructions can be used to jump to any address.
* Data memory size is 640 bytes. RAM access is done in the same way as access to I/O ports. First, a SRC instruction is used to tell the processor what memory address to access, and successive WRM or RDM writes accumulator data to memory or reads data into accumulator. Data memory is separate from program memory.
Stack is 3-level deep (3 x 12-bit registers). Stack is separate from program memory and data memory.
Interrupts
None.
* I/O ports
16 4-bit input ports.16 4-bit output ports.
Registers
* Program counter (12-bit).
* Stack registers. There are three 12-bit stack level registers, which is sufficient to implement 3-level deep subroutine calls. Every subroutine call stores return address in one of the stack registers. Contents of the accumulator and the index registers is not preserved.
* Accumulator (4-bit). Mainly used for arithmetic and logic operations, as well as for reading and writing data from/to RAM and I/O ports.
Index registers. The microprocessor has 16 4-bit registers, that can work in pairs as 8 8-bit registers.
Instruction Set
4004 instruction set consists of 46 instructions:
· Data moving instructions.
· Arithmetic - add, subtract, increment, decrement.
· Logic - rotate.
· Control transfer - conditional (limited to current ROM), unconditional, call subroutine and return from subroutine.
· Input/Output instructions.
· Other - carry flag operations, decimal adjust, etc.
Instruction length can be one or two bytes.
* Addressing modes
Register (4-bit).Memory direct.Register indirect. Register indirect can access data only within current ROM.Immediate (4 and 8-bit data).

CHARACTERISTICS OF FEW 40004 CHIPS:
* C4004 -White/Gold CerDIP, 16-pin (visible traces)
- Gray trace chips were produced from 1971-76. This chip was assembled in Malaysia.
-White/Gold CerDIP, 16-pin
-I have chips assembled in the US and Hong Kong
- Gray Ceramic, 16-pin DIP
* D4004 -Assembled in Malaysia
-Black Resin, 16-pin DIP
-Assembled in the Philippines
-Gray Resin, 16-pin DIP
-Gray resin chips were produced from 1971-73 Architecture



* INTEL C4004:

740 KHz16-pin ceramic DIP4004 (C4004) processors in white ceramic package were produced until the second half of 1976. This particular processor is dated 8th week of 1975. Today the C4004 with visible traces (like the one on the picture) is the most rare and expensive version of Intel 4004.

* INTEL D4004:
16-pi KHz ceramic DIPn4004 microprocessors 740 in plastic and ceramic (not white ceramic) packages were introduced around 1976. This ceramic 4004 is dated 45th week of 1976.

* INTEL P4004:

740 KHz16-pin plastic
* NATIONAL SEMICONDUCTOR iNS4004D:
16-pin ceramic DIPPurple ceramic/gold top/gold pinsNational Semiconductor was the only second source company for the Intel 4004. The naming convention for the 4004 processors was "INS4004" plus one letter representing package type. The chip on the picture is mistakenly marked as "iNS4004D" .

TECHNICAL APPLICATIONS:
Maximum 740clock speed is kHzAll of Intel's 4004 data sheets, including the very first data sheet from November 1971, clearly indicate that the minimum clock period is 1350 nanoseconds, which results in a maximum clock speed of 740 kHz. Unfortunately, many apparently reputable web pages and other sources list an incorrect clock speed of 108 kHz; even Intel's own pages on the 4004's history say this. The 4004's minimum instruction cycle time is 10.8 microseconds (8 clock cycles), and it seems most likely that someone in the past confused this with a clock speed. This error has now propagated very widely.*Separate program and data storage (i.e., a Harvard architecture). Contrary to most Harvard architecture designs, however, which use separate buses, the 4004, with its need to keep pin count down, uses a single multiplexed 4-bit bus for transferring:** 12-bit addresses** 8-bit instructions** 4-bit data words*Instruction set contains 46 instructions (of which 41 are 8 bits wide and 5 are 16 bits wide)*Register set contains 16 registers of 4 bits each*Internal subroutine stack is 3 levels deep
Microarchitecture and pinout.

CONCLUSION:

Thus we studied about the first single chip microprocessor and its technical aspects.Mre over we came across the instruction set and different microprocessor family. Anyway this single chip microprocessor acts as the the starting of all the evolution of newer developments.