Table 2 Microcontroller pin description5 PIN NO PIN

Table 2. Microcontroller pin description[5] PIN NO. PIN NAME DESCRIPTION 1 (XCK/T 0) PBO I/O PORT B, Pin 0 2 (T 1) PB 1 I/O PORT B, Pin 1 3 (INT 2/AINO) PB 2 I/O PORT B, Pin 2 4 (OC 0/AIN 1) PB 3 I/O PORT B, Pin 3 5 6 7 8 9 10 11 12 (SS) PB 4 (MOSI) PB 5 (MISO) PB 6 (SCK) PB 7 RESET Vcc GND XTAL 2 I/O PORT B, Pin 4 I/O PORT B, Pin 5 I/O PORT B, Pin 6 I/O PORT B, Pin 7 Reset Pin, Active Low Reset Vcc=+5 V GROUND Output to Inverting Oscillator Amplifier 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 XTAL 1 (RXD) PDO (TXD) PD 1 (INT 0) PD 2 (INT 1) PD 3 (OC 1 B) PD 4 (OC 1 A) PD 5 (ICP) PD 6 PD 7 (OC 2) PC 0 (SCL) PC 1 (SDA) PC 2 (TCK) PC 3 (TMS) PC 4 (TDO) PC 5 (TDI) PC 6 (TOSC 1) PC 7 (TOSC 2) AVcc GND Input to Inverting Oscillator Amplifier I/O PORT D, Pin 0 I/O PORT D, Pin 1 I/O PORT D, Pin 2 I/O PORT D, Pin 3 I/O PORT D, Pin 4 I/O PORT D, Pin 5 I/O PORT D, Pin 6 I/O PORT D, Pin 7 I/O PORT C, Pin 0 I/O PORT C, Pin 1 I/O PORT C, Pin 2 I/O PORT C, Pin 3 I/O PORT C, Pin 4 I/O PORT C, Pin 5 I/O PORT C, Pin 6 I/O PORT C, Pin 7 Voltage Supply = Vcc for ADC GROUND 32 33 34 35 36 37 38 39 40 AREF PA 7 (ADC 7) PA 6 (ADC 6) PA 5 (ADC 5) PA 4 (ADC 4) PA 3 (ADC 3) PA 2 (ADC 2) PA 1 (ADC 1) PA 0 (ADC 0) Analog Reference Pin for ADC I/O PORTA, Pin 7 I/O PORTA, Pin 6 I/O PORTA, Pin 5 I/O PORTA, Pin 4 I/O PORTA, Pin 3 I/O PORTA, Pin 2 I/O PORTA, Pin 1 I/O PORTA, Pin 0 ALTERNATE FUNCTION T 0: timer 0 external counter input. XCK: USART External Clock I/O T 1: Timer 1 External Counter Input AINO: Analog Comparator Positive I/P INT 2: External Interrupt 2 Input AIN 1: Analog Comparator Negative I/P OC 0: Timer 0 Output Compare Match Output In System Programmer(ISP) Serial Peripheral Interface(SPI) USART Serial Communication Interface External Interrupt INT 0 External Interrupt INT 1 PWM Channel Outputs Timer/Counter 1 Input Capture Pin Timer/Counter 2 Output Compare Match Output TW 1 Interface JTAG Interface Timer Oscillator Pin 1 Timer Oscillator Pin 2 ADC Channel 7 ADC Channel 6 ADC Channel 5 ADC Channel 4 ADC Channel 3 ADC Channel 2 ADC Channel 1 ADC Channel 0 M. Ehikhamenle et al. Design and Development of a Smart Digital Tachometer Using At 89 c 52 Microcontroller. American Journal of Electrical and Electronic Engineering, 2017, Vol. 5, No. 1, 1 -9. doi: 10. 12691/ajeee-5 -1 -1 © The Author(s) 2015. Published by Science and Education Publishing.