diff --git a/Intro-Arduino.adoc b/Intro-Arduino.adoc
index dd54563..d079571 100644
--- a/Intro-Arduino.adoc
+++ b/Intro-Arduino.adoc
@@ -66,6 +66,31 @@ void loop() {
 ```
 
 
+== Pin Description
+
+.Pin Description
+[options="header,footer"]
+|=======================
+|Pin Category|Pin Name|Details
+|Power|Vin, 3.3V, 5V, GND|
+* Vin: Input voltage to Arduino when using an external power source. 
+* 5V: Regulated power supply used to power microcontroller and other components on the board.
+* 3.3V: 3.3V supply generated by on-board voltage regulator. Maximum current draw is 50mA.
+* GND: ground pins.
+|Reset|Reset|
+			Resets the microcontroller.
+| Analog Pins|A0 – A5|Used to provide analog input in the range of 0-5V
+|Input/Output Pins|Digital Pins 0 - 13|Can be used as input or output pins.
+|Serial|0(Rx), 1(Tx)|Used to receive and transmit TTL serial data.
+|External Interrupts|2, 3|To trigger an interrupt.
+|PWM|3, 5, 6, 9, 11|Provides 8-bit PWM output.
+|SPI|10 (SS), 11 (MOSI), 12 (MISO) and 13 (SCK)|Used for SPI communication.
+|Inbuilt LED|13|To turn on the inbuilt LED.
+|TWI|A4 (SDA), A5 (SCA)|Used for TWI communication.
+|AREF|AREF|To provide reference voltage for input voltage.
+|=======================
+
+
 
 
 :hardbreaks: