Features of 8051 and 8051 Family Microcontrollers

Features of 8051 and 8051 Family Microcontrollers

AU : Dec.-04, May-12, 16

The 8051 is an 8-bit microcontroller designed by Intel. It was optimized for 8-bit math and single bit Boolean operations. Its family includes 8031, 8051, 8052 and 8751 microcontrollers. Let us see the features of 8051 microcontroller.

The features of the 8051 family are as follows :

1. 4096 bytes on - chip program memory.

2. 128 bytes on - chip data memory.

3. Four register banks.

4. 128 user-defined software flags.

5. 64 kilobytes each program and external RAM addressability.

6. One microsecond instruction cycle with 12 MHz crystal.

7. 32 bidirectional I/O lines organized as four 8-bit ports (16 lines on 8031).

8. Multiple mode, high-speed programmable serial port.

9. Two multiple mode, 16-bit timers/counters.

10. Two-level prioritized interrupt structure.

11. Full depth stack for subroutine return linkage and data storage.

12. Direct byte and bit addressability.

13. Binary or decimal arithmetic.

14. Signed-overflow detection and parity computation.

15. Hardware multiple and divide in 4 psec.

16. Integrated boolean processor for control applications.

17. Upwardly compatible with existing 8084 software.

The Table 14.2.1 gives the comparison of MCS-51 family microcontrollers.

As shown in the Table 14.2.1, the 8052 has an extra 128 bytes of RAM, 4 K extra ROM, extra timer and one more interrupt source than the 8051 microcontroller. The 8052 maintains the source compatibility with 8051. This means that all programs written for the 8051 will run on 8052; however, reverse is not true.

The 8751 microcontroller has 4 K of EPROM instead of ROM. This allows to erase and reprogram the contents of program memory within 8751. It takes around 20 minutes to erase the 8751 before it can be programmed again. This feature is very useful in the program development stage.

Review Questions

1. List the features of 8051 microcontroller.

2. Compare the 8051, 8031 and 8751 microcontroller.

3. List out the hardware resources available in 8051. AU : Dec.-04

4. What are the main features of 8051 microcontroller ? AU : May-12, Marks 2