Tag archives for PIC18 Peripheral Libraries
LCDs are alphanumeric (or graphical) displays, which are frequently used in microcontroller based applications which require some information to be displayed to the user. There are many devices in the market which come in different shapes and sizes. Some LCDs have 40 or more character lengths with the capability to display several lines. Some other LCD displays can be programmed to display graphic images. Some modules offer color displays, while some others incorporate back lighting so that they can be viewed in dimly lit conditions. In this tutorial we will learn how to connect an LCD to any PORT of a microcontroller, display characters and send commands to LCD using lcd library with MPLAB Code Configurator and PIC18F Peripheral Libraries.
Analog to Digital converters allow analog continuous voltages to be converted into a discreet digital numbers inside the PIC as the PIC can only process digital numbers. This can enable a PIC to be connected to analog sensors such as temperature sensors, pressure sensors, humidity sensors, optical sensors, and power sensors. Any sensor which can generate a voltage between 0V and a maximum 5V can be used. If the output voltage is higher than 5V, a method to step it down should be used such as a voltage divider with resistors.
The DS1307 is a low power serial real time clock/calender with full binary coded decimal (BCD) clock/calendar plus 56 bytes of Non Volatile Static RAM. The RTC provides year, month, date, hour, minute and second information. The end date of months is automatically adjusted for months fewer than 31 days including leap year compensation up to year 2100. It can operate either in 24-hour format or 12-hour format with AM/PM indicator. Data and Address are transferred serially through a bidirectional I2C bus. DS1307 comes with built-in power sensing circuit which senses power failures and automatically switches to back up supply. Timekeeping operation continues while the part operates from the backup supply. The DS1307 RTC uses an external 32.768kHz Crystal Oscillator and it does not requires any external resistors or capacitors to operate.
There are three types of memories in a PIC Microcontroller, The Flash Program Memory, The Data Memory (RAM) and The EEPROM Data Memory. The code that is written by the user to perform a specific task by the microcontroller is stored in the Flash. Flash memory makes it possible to program a microcontroller many times because it is re-writable, this memory can be written into and erased many times. RAM Data Memory is used for storing data temporarily during program execution and it is volatile. The third memory is EEPROM memory which is an abbreviation for Electrically Erasable Programmable Read Only Memory. EEPROM memory can be read and write electrically, can be accessed through program. It is a non volatile memory but has slower response time. EEPROM memory can be used to store data which should not be loss during power loss or CPU reset. such data could be like device parameters or settings which could be entered once and stored in the EEPROM. In this article, we will learn how to read or write data to the microcontroller built-in EEPROM.