Applications for the Matrix Keypad MCS51 Hexadecimal

Hexadecimal keypad matrix can be created with a microcontroller by using the parallel port MCS51. Hexadecimal keypad matrix system is working by reading the data on tiab line through each column or vice versa depending on the program. To make enough Hexadecimal keypad matrix with 1 port MCS51 microcontroller. With 1 parallel port, the microcontroller can be made Matrix Keypad Hexadecimal 4 columns and 4 lines or so-disebud with 4 × 4 matrix keypad. Hexadecimal Keypad Matrix 4 × 4 is in pernacangannya will provide data Hexadecimal 0 - F.

Parallel port for MCS51 Microcontroller Matrix Keypad
The parallel port is part of the most widely used microcontroller. Ranging from things very simple for example to turn on the LED or read button, used also to form a hexadecimal keypad, to control the stepper motor and connecting the microcontroller to the printer parallel.

In general the parallel port is said to be a means of input / output that can be used to transfer data several bits (typically 8 bits) once gus through lane (feet IC) prepared for it. The path are numbered from 0 to 7, in accordance with the serial number of bits in the accumulator that was used to trasfer data to / from the parallel port. For example, the accumulator is used to receive data from Port 0, then the line number 0 of Port 0 (usually abbreviated as P0.0) will be transferred to the accumulator bit number 0 (usually abbreviated as A.0).

Almost all microcontroller IC legs can be used as a parallel port. AT89C2051 legs 20, 15 feet can be used as a parallel port. AT89C51-footed 40 of them 32 feet can be used as a parallel port.

Nevertheless, there is also a parallel port that does not consist of an 8-lane, for example, Port 1 of AT89C2051 only consists of 7 lines, numbered ranging from P1.0 to P1.7, P1.6 but no. This sort of thing is usually caused by the IC legs are available are not sufficient to contain all relevant path parallel port is complete.

All lines on the parallel port (except Port 0) MCS51 equipped with about 50 kOhm resistance, corresponding to a path connecting Vcc resources. On chip AT89C1051, AT89C2051 and AT89C4051, Port 1 path 0 and 1 (P1.0 and P1.1) are not equipped with these detainees, as a result if both paths are used as outputs must be added detainees outside AT89C2051, which connects the pathways to a power source Vcc.

4 x 4 Matrix Keypad Hexadecimal
Matrix Keypad 4 × 4 is an arrangement of 16 buttons form the keypad as a means to enter into the microcontroller, although the number of buttons there are 16 but only require an 8-lane parallel ports, as shown in the picture below.

In the circuit in the image above, each button connects an output line (K1, K2, K3 or K4) into a line input (B1, B2, B3 or B4), as described in detail in the lower right circle images, buttons "A" connecting path to the lane B4 K1. Working from a series of keypad is fully implemented with the software.