| RAM 368 EEPROM 256 bytes Flash Program Memory 8k words Operating Frequency DC to 20MHz I/O port Port A,B,C,D,E This is the specification for PIC16F877A from Microchip. A single microcontroller which is very brilliant and useful. Also this microcontroller is very easy to be assembled, program and also the price is very cheap. It cost less than 10 dollar. The good thing is that single unit can be purchased at that 10 dollar price. Unlike some other Integrated Circuit that must be bought at a minimum order quantity such as 1000 units or 2000 units or else you won’t be able to purchase it. One unit of PIC16F877A microcontroller can be programmed and erased so many times. Some said about 10 000 times. If you are doing programming and downloading your code into the PIC 20 times a day, that means you can do that for 500 days which is more than a year! The erasing time is almost unnoticeable because once new program are loaded into the PIC, the old program will automatically be erased immediately. During my time of Degree study, I did not use PIC but I use other type of microcontroller. I have to wait for about 15 to 30 minutes to erase the EEPROM before I can load a new program and test the micrcontroller. One day I can only modify my code and test it for less than 10 times. 10x15 minutes = 150 minutes. PIC16F877A already made with 368 bytes of Random Access Memory (RAM) inside it. Any temporary variable storage that we wrote in our program will be stored inside the RAM. Using this microcontroller you don’t need to buy any external RAM. 256 bytes of EEPROM are available also inside this microcontroller. This is very useful to store information such as PIN Number, Serial Number and so on. Using EEPROM is very important because data stored inside EEPROM will be retained when power supply is turn off. RAM did not store data permanently. Data inside RAM is not retained when power supply is turn off. The size of program code that can be stored is about 8k words inside PIC16F877A ROM. 1 word size is 14 bits. By using the free version of the CCS C compiler only 2k words of program can be written and compiled. To write 8k words of C program you have to purchase the original CCS C compiler and it cost less than 700 dollar. The crystal oscillator speed that can be connected to the PIC microcontroller range from DC to 20Mhz. Using the CCS C compiler normally 20Mhz oscillator will be used and the price is very cheap. The 20Mhz crystal oscillator should be connected with about 22pF capacitor. Please refer to my circuit schematic. There are 5 input/output port on PIC microcontroller namely port A, port B, port C, port D and port E. Each port have diffent function. Most of them can be used as I/O port. Next Page >> |
| PIC16F877A Microcontroller |