74HC595 Module

74hc595 24 Bit IO Expansion Board

24 Digital Output Pin Multiplexing Increase Led Panel Driving 7 Segment Bargraph Relay Control Serial Parallel Shift Register

     It is an IO port expansion board formed by connecting three 74HC595 serial input, parallel output shift register chips in series (cascade). It eliminates the “insufficient pins” problem frequently encountered in simple microcontroller projects. It allows your microcontroller to expand to a total of 24 output ports using only three normal IO pins (via the LDEN, LDSI, LDSTR, LDCK pins). Thanks to this, you can save pins in complex circuits or in projects requiring the control of many leds.

     It is compatible with Arduino, stm32, esp32, avr and all other microcontrollers. Thanks to the 74HC595 register, data is loaded serially, and all outputs are updated at the same time with the latch signal. It can be used in led driving, relay control, indicator panels, segment display applications and in every project requiring multiple digital outputs. The 3 integrated circuits on the board are marked as U1, U2, U3 respectively, and there are a total of 24 outputs on the pads at the bottom part in the form of Q0–Q7, Q0–Q7, Q0–Q7.

     How Does It Work? This module is based on 24 bit data being shifted in order and loaded into the chips with the serial data input (DS/LDSI) and clock pulse (SHCP/LDCK) of the 74HC595. After all the data is loaded, the Latch pin (STCP/LDSTR) is raised and the 24 bit data is instantly transferred to the parallel outputs (Q0-Q7). Thanks to this, you can control 24 different outputs with only 3 pins of your microcontroller.

     Note: This module is only for output expansion. To read input, parallel-serial shift register modules such as the 74HC165 must be used.
Do not exceed the maximum output current values. Use suitable current limiting resistors when using LEDs. Use it with a ULN2803 or MOSFET driver in high current applications.

Features

• Integrated circuit:  3 74HC595 integrated circuits connected in series
• Total number of outputs:  24 pieces (3 × 8 bit)
• Control method:  Serial Input – Parallel Output (SPI like)
• Operating voltage: DC 2V / 6V
• Maximum operating current of each output: 30mA
• Total output current: Maximum 500mA
• Compatible with all microcontrollers (Arduino, stm32, esp32, pic etc.)
• More 74HC595 can be added with the vst and data lines at the module ends
• Q0…Q7, output naming in 3 groups
• Control pins:  DATA, CLOCK, LATCH
• Operating temperature:  -20C  /  65C
• Color:  Purple
• Dimensions:   19,5mm x 61mm
• Weight:  8.5gr

Pin descriptions:

• Left side (control inputs):
  • LDEN:  Output Enable (Output Enable - active when Low)
  • GND:  Ground Connection
  • VCC:  Supply DC 2V / 6V
  • LDSI:  Serial Data Input (Data In)
  • LDSTR:  Register Latch (Latch Clock - Transfers the Data to the Output)
  • LDSCK:  Clock Signal Input (Shift Register Clock)
• Right side (output for chaining):
  • LDEN:  Output Enable (Output Enable - active when Low)
  • GND:  Ground Connection
  • VCC:  Supply DC 2V / 6V
  • Q0 - Q7 (Bottom row)    24 parallel output pins (from the 0th Register to the 7th Register)
  • LDSTR:   Register Latch (Latch Clock - Transfers the Data to the Output)
  • LDSCK:  Clock Signal Input (Shift Register Clock)

Areas of use:

• LED strip, dot LED arrays
• 7-segment display driving
• Button or indicator panels
• Relay driver boards
• Matrix display systems
• Industrial control circuits
• Pin expansion on microcontroller boards

Package contents:

•     1 Piece 74HC595 24 Bit IO Board
•      40 pin 90 degree male header socket.