Hardware and Development

PIC 16F877A

 

 PIC16F877A-I/P microcontroller is used to control the whole system. It is designed using flash technology. So the PIC can read/write program for more than 100,000 times. The PIC 16F877A has 8 K words or program memory. Since each word in the midrange family is 14 bits long the program memory can also be expressed as 14 Kbytes. The unit has 368 bytes of data ram and 256 bytes of EEPROM. It has 8 channels of A/D with 10 bit resolution. The unit has 2 8 bit Timer/Counters and a single 16 bit Timer/Counter. In addition to this it has several different types of serial communication functions such as SPI, I2C, and normal pc type serial communications functions.

                                                                                

                                                                               

OSC1 and OSC2 pins are connected to 20MHz crystal to execute every single program line in the system.  20MHz crystal is used because this is the maximum frequency that the PIC can support. If over frequency the PIC will burn. Else if crystal speed less than 20MHz then PIC response speed will slower. The MCLR pin of the PIC is pull up to 5V through a 10KR resistor. 

 

                                      

key features for several types of PIC16F