74HC74 - Dual D-type Positive Edge-triggered Flip-Flops IC
74HC74 - Dual D-type Positive Edge-triggered Flip-Flops IC
The 74HC74 is a dual D-type positive edge-triggered flip-flop integrated circuit (IC) that belongs to the 74HC family of CMOS logic devices. It is a widely used component in digital electronic systems, particularly in applications requiring flip-flop functionality.
The 74HC74 IC consists of two identical, independent D-type flip-flops, each with a positive edge-triggered clock input. The device operates by storing the input data (D) in the flip-flop when the clock (CLK) input transitions from a low to a high voltage level (positive edge). The output (Q) follows the input data, and the inverted output (Q') is the complement of the output.
| The 74HC74 can be used in various digital circuits, such as |
| The 74HC74 IC has a 14-pin dual in-line package (DIP) or a surface-mount package (SOT) with the following pin configuration |
| Pin Number | Pin Name | Function |
| --- | --- | --- |
| 1 | Q1 | Output of Flip-Flop 1 |
| 2 | Q1' | Inverted Output of Flip-Flop 1 |
| 3 | D1 | Data Input of Flip-Flop 1 |
| 4 | CLK1 | Clock Input of Flip-Flop 1 |
| 5 | SET1 | Asynchronous Set Input of Flip-Flop 1 |
| 6 | RST1 | Asynchronous Reset Input of Flip-Flop 1 |
| 7 | VCC | Positive Power Supply |
| 8 | GND | Ground |
| 9 | RST2 | Asynchronous Reset Input of Flip-Flop 2 |
| 10 | SET2 | Asynchronous Set Input of Flip-Flop 2 |
| 11 | CLK2 | Clock Input of Flip-Flop 2 |
| 12 | D2 | Data Input of Flip-Flop 2 |
| 13 | Q2' | Inverted Output of Flip-Flop 2 |
| 14 | Q2 | Output of Flip-Flop 2 |
| The 74HC74 is widely used in digital electronic systems, including |
By providing a detailed description of the 74HC74 IC, this documentation aims to facilitate the understanding and implementation of this component in various digital electronic systems.
74HC74 - Dual D-type Positive Edge-triggered Flip-Flops ICOverviewThe 74HC74 is a dual D-type positive edge-triggered flip-flop IC, a crucial component in digital electronic circuits. It is a popular choice for building sequential logic circuits, counters, and registers. This IC consists of two identical flip-flops, each with a clock input (CP), data input (D), and two outputs (Q and Q'). The flip-flops are triggered on the positive edge of the clock signal, and the outputs change state on the rising edge of the clock.PinoutThe 74HC74 IC has a 14-pin package, with the following pinout:Pin 1: CP1 (Clock input for Flip-Flop 1)
Pin 2: D1 (Data input for Flip-Flop 1)
Pin 3: Q1 (Output for Flip-Flop 1)
Pin 4: Q1' (Complementary output for Flip-Flop 1)
Pin 5: VCC (Power supply voltage)
Pin 6: GND (Ground)
Pin 7: Q2' (Complementary output for Flip-Flop 2)
Pin 8: Q2 (Output for Flip-Flop 2)
Pin 9: D2 (Data input for Flip-Flop 2)
Pin 10: CP2 (Clock input for Flip-Flop 2)
Pin 11-14: NC (No connection)Truth TableThe truth table for the 74HC74 flip-flop is as follows:| CP (Clock) | D (Data) | Q (Output) | Q' (Complementary Output) |
| --- | --- | --- | --- |
| 0 (Low) | X (Don't care) | Qprev (Previous state) | Qprev' (Previous complementary state) |
| 1 (High) | 0 (Low) | 0 (Low) | 1 (High) |
| 1 (High) | 1 (High) | 1 (High) | 0 (Low) |Code ExamplesHere are two code examples that demonstrate how to use the 74HC74 IC in different contexts:Example 1: Simple Flip-Flop Counter (Arduino)In this example, we will use the 74HC74 IC to create a simple binary counter. We will connect the clock input to a digital output pin on an Arduino board, and the outputs to LEDs.```c++
const int clockPin = 2; // Clock input for the flip-flop
const int q1Pin = 3; // Output Q1
const int q2Pin = 4; // Output Q2void setup() {
pinMode(clockPin, OUTPUT);
pinMode(q1Pin, INPUT);
pinMode(q2Pin, INPUT);
}void loop() {
digitalWrite(clockPin, HIGH); // Clock pulse
delay(500);
digitalWrite(clockPin, LOW);
delay(500);
}
```Example 2: Shift Register using 74HC74 (Raspberry Pi, Python)In this example, we will use two 74HC74 ICs to create a 4-bit shift register. We will connect the clock inputs to a digital output pin on a Raspberry Pi, and the outputs to LEDs.```python
import RPi.GPIO as GPIO
import time# Set up GPIO mode
GPIO.setmode(GPIO.BCM)# Define clock and data pins
clockPin = 17
dataPin = 23# Set up pins as outputs
GPIO.setup(clockPin, GPIO.OUT)
GPIO.setup(dataPin, GPIO.OUT)# Define output pins for the shift register
q1Pin = 24
q2Pin = 25
q3Pin = 5
q4Pin = 6# Set up pins as inputs
GPIO.setup(q1Pin, GPIO.IN)
GPIO.setup(q2Pin, GPIO.IN)
GPIO.setup(q3Pin, GPIO.IN)
GPIO.setup(q4Pin, GPIO.IN)# Initialize the shift register
GPIO.output(dataPin, GPIO.LOW)while True:
# Shift in a '1' bit
GPIO.output(dataPin, GPIO.HIGH)
GPIO.output(clockPin, GPIO.HIGH)
time.sleep(0.1)
GPIO.output(clockPin, GPIO.LOW)
time.sleep(0.1)
# Shift in a '0' bit
GPIO.output(dataPin, GPIO.LOW)
GPIO.output(clockPin, GPIO.HIGH)
time.sleep(0.1)
GPIO.output(clockPin, GPIO.LOW)
time.sleep(0.1)
```These examples demonstrate the basic usage of the 74HC74 IC in different contexts. The IC can be used in a wide range of applications, including sequential logic circuits, counters, registers, and shift registers.