I/O pins, Ports and Circuits

One major feature of a microcontroller is the versatility built into the input/output (I/O) circuits that connect the 8051 to the outside world. As noted in microprocessor designs must add additional chips to interface with external circuitry; this ability is built into the microcontroller. To be commercially viable, the 8051 had to incorporate as many …

Familiarize with 8051 Architecture

Program Counter and Data Pointer The 8051 contains two 16-bit registers-the program counter(PC) and data pointer(DPTR). Each is used to hold the address of a byte in memory. Program instruction bytes are fetched from locations in memory that are addressed by PC. Program ROM may be on the chip at address 000h to 0FFFh, external …

Pin Description of 8051

The 8051 packaged in a 40-pin DIP. The figure shows the pin diagram of 8051. Many of the pins of 8051 are used for more than one function. The alternative functions are also shown in the diagram. The 8051 has 32 I/O pins configured as four eight-bit parallel ports(P0, P1, P2 and P3). All four …

8051: Unique Features

The 8051 microcontroller is generic part number actually includes a whole family of microcontrollers that have numbers ranging from 8031 to 8751 and are available in N-channel Metal Oxide Silicon(NMOS) and Complimentary Metal Oxide Silicon(CMOS) constructed in a variety of package types. The unique features of 8051 are;  Internal RAM and ROM * I/O ports …