What is 8051?

The 8051 is a popular 8-bit single chip microcontroller which was first introduced by Intel. The first 8051 is a 40-pin microcontroller which has 4kB of program memory, 128 bytes of RAM, 2 timer/counter, 1 UART, and six interrupt sources.

Later on, the 8052 microcontroller was introduced. The 8052 microcontroller is a better version of 8051 microcontroller. It has 8kB of code memory and 256 bytes of RAM. It also has an additional timer.

8051 became very propular and it became an industry standard. Due to its popularity, many semiconductor manufacturers like Atmel, Infineon Technologies, Maxim Integrated Products, NXP, ST Microelectronics, Silicon Laboratories, Texas Instruments, Cypress Semiconductor, etc have included 8051 in their line of products.

What is AT89C2051?

AT89C2051is manufactured by Atmel and it is a member of 8051 family of microcontrollers. Unlike the original 8051 microcontroller which has 40 pins, AT89C2051 has only 20 pins which makes it ideal for 8051 beginners. It takes the standard features of the original features of 8051 except that it has only 20 pins compared to 40 pins of the original 8051. However, AT89C2051 is made of flash program memory and it has additional on-chip analog comparator.