8051 Microcontroller
- 8051 is a most revolutionary set of microcontrollers.
- The 8052 microcontroller has 256 bytes of RAM and 3 timers.
- Programs written for 8051 microcontroller can be used for 8052.
- The 8031 has all features of 8051 except that it is no internal ROM.
- An external ROM that can be interfaced is 64 k bytes which can be programmed and connected to this chip for execution.
- The main disadvantage of connecting external ROM is that 2 out of 4 ports are used as a address and data bus. The different types of memory used in 8051 family are:
- Internal RAM
- Special Function Registers (SFR)
- Program Memory
- External Data Memory
- Intel Corporation had developed first 8 bit microcontroller i.e. 8051 in 1981 and was called as a “system on a chip” because it had 128 bytes of RAM, 4 Kbytes of ROM, 2 Timers, 1 Serial port, interrupt system, power reduction mode i.e. Idle and Power Down and four ports on a single chip.
- Later, Intel other microcontroller manufacturers like Dallas, Atmel, Phillips etc. to fabricate different versions of 8051 with the condition that code compatibility should be maintained.
- The advantage of this is that when the program is written, you can be used it for any version of 8051 of any manufacturer.