16×2 alphanumeric LCD can display 16 characters in each of its row, and it has two rows. To interface an LCD we need to know about its internal registers and pin functions. An LCD has two important registers namely command register and Data register. Both are 8-bit registers. The command register is written with various commands by the user. These commands are responsible for the functioning of LCD. 16×2 LCD is widely used in various embedded applications. The reason for this is its easy operation and it can display a large number of characters and symbols. In this tutorial we’ll interface LCD with ARM7 based microcontroller LPC2138.LCD can be interfaced in 8-bit as well as 4-bit mode (mode signifies Data bits sent at a time). In the 8-bit mode we require 8-pins of the microcontroller whereas in 4-bit mode the data is sent ‘nibble’ by ‘nibble’ (4 data lines used).
Seven segment displays are very commonly used in meter displays, etc. In this tutorial we’ll interface seven segment display(s) to our ARM7 based microcontroller LPC2138. For those who are new to ARM refer to previous tutorial (LED Interfacing). The task is to display all Numbers (0-9) and Alphabets on SSD. LPC2138 is a 32-bit microcontroller, so while coding we’ll be dealing with IO Registers that are 32-bit wide. For Interfacing a 7-segment we choose P0 (P0.0 to P0.7; 8 Pins out of 32 IO Pins on Port-0).Let’s use a common anode type display, a simple push-button switch, Resistors, etc. a,b,c,d,e,f terminals of display are connected to P0.0 to P0.6 respectively. Common terminal is supplied with +Vcc through a current limiting resistor R. Keep on reading to find out how whole system is assembled and what coding is applied to make it work.
With the exponentially increasing modernization in Electronics Field, particularly in Embedded systems, it’s now a necessary step for Engineers, students and hobbyists to move along with Industry. There’s a need to grasp skills on recent industrial tools and systems. ARM Processors are one of such advancements in Embedded stream which serve as major platform for many of the modern systems. ARM stands for 32 bit Advanced RISC (Reduced Instruction Set Computer) Machines designed and licensed by British company ARM Holdings. As an IP core business, ARM Holdings itself does not manufacture its own electronic chips, but licenses its designs to other semiconductor manufacturers. ARM-based processors and systems on a chip include the Qualcomm Snapdragon, TI, etc. Using a RISC based approach to computer design, ARM processors require significantly fewer transistors than processors that would typically be found in a traditional computer.