Apr 15, 2013 - INTERFACING LEDs TO ARM 7 CONTROLLER- (LPC2148 )Light. ComPROGRAM -1This program blinks the LEDs continuously with a small delay. By applying the code in the reverse order, the stepper motor can be. ARM7 LPC21xx processor is interfaced to the 2x16 LCD mpdule in 4-bit mode. Interfacing of LCD with ARM including c program of lcd interfacing with LPC2148 types of LCD with proteus simulation file.

Here ARM LPC2129 Mini Development Board is interfaced with a LCD module (2×16) operating at 5V. The voltage at the third pin of the LCD used to adjusting contrast.

LCD can work either in 4 or 8 bit mode. Here, the circuit is designed to work in 4bit mode. Control lines (RS, R/W,E) are connected to port pins P1.17,P1.18, P1.19 and data lines (D4-D7) to port pins P1.20,P1.21,P1.22,P1.23 in 4bit mode. For reliable Performance, LCD has to be initialized. On powering microcontroller send initialization commands to LCD for better working. The sample code below gives LCD display output ” RhydoLABZ ” in line 1 and “ Cochin” in line 2.

Gratis buku belajar membaca untuk anak tk diterkam 3. Schematic: Sample code.

Contents • • • • • • • • • • • • LCD UNIT Let us look at a pin diagram of a commercially available LCD like JHD162 which uses a HD44780 controller and then describe its operation. Pin Number Symbol Pin Function 1 VSS Ground 2 VCC +5v 3 VEE Contrast adjustment (VO) 4 RS Register Select.

0:Command, 1: Data 5 R/W Read/Write, R/W=0: Write & R/W=1: Read 6 EN Enable. Falling edge triggered 7 D0 Data Bit 0 8 D1 Data Bit 1 9 D2 Data Bit 2 10 D3 Data Bit 3 11 D4 Data Bit 4 12 D5 Data Bit 5 13 D6 Data Bit 6 14 D7 Data Bit 7/Busy Flag 15 A/LED+ Back-light Anode(+) 16 K/LED- Back-Light Cathode(-) Apart from the voltage supply connections the important pins from the programming perspective are the data lines(8-bit Data bus), Register select, Read/Write and Enable pin. Data Bus: As shown in the above figure and table, an alphanumeric LCD has an 8-bit data bus referenced as D0-D7. As it is an 8-bit data bus, we can send the data/cmd to LCD in bytes. It also provides the provision to send the data/cmd in chunks of 4-bit, which is used when there are limited number of GPIO lines on the microcontroller.

Register Select(RS): The LCD has two register namely a Data register and Command register. Any data that needs to be displayed on the LCD has to be written to the data register of LCD. Command can be issued to LCD by writing it to Command register of LCD. This signal is used to differentiate the data/cmd received by the LCD. If the RS signal is LOW then the LCD interprets the 8-bit info as Command and writes it Command register and performs the action as per the command. If the RS signal is HIGH then the LCD interprets the 8-bit info as data and copies it to data register. After that the LCD decodes the data for generating the 5x7 pattern and finally displays on the LCD.

Read/Write(RW): This signal is used to write the data/cmd to LCD and reads the busy flag of LCD. For write operation the RW should be LOW and for read operation the R/W should be HIGH. Enable(EN): This pin is used to send the enable trigger to LCD. After sending the data/cmd, Selecting the data/cmd register, Selecting the Write operation. An HIGH-to-LOW pulse has to be sent on this enable pin which will latch the info into the LCD register and triggers the LCD to act accordingly. Schematic Below schematic shows the minimum connection required for interfacing the LCD with the microcontroller.