nanoFramework.Iot.Device.Sn74hc595 1.2.159

SN74HC595 -- 8-bit shift register

SN74HC595 is a 8-bit shift register. Per the datasheet, the SN74HC595 is a "8-Bit Shift Register With 3-State Output Register". The Sn74hc595 binding is based on and is compatible with the more general ShiftRegister binding. The Sn74hc595 binding adds the ability clear the storage register with a single pin. Either binding can be used to control the SN74HC595.

The binding abstracts the interaction with the data register, the register clock and other shift register capabilities. The binding enables interaction via GPIO or SPI.

Documentation

• Datasheet
• Adafruit
• Tutorial

Usage

The following example code demonstrates how to use the SN74HC595 with its most basic functions.

Sn74hc595 sr = new(Sn74hc595PinMapping.Minimal);

// Light up three of first four LEDs
sr.ShiftBit(1);
sr.ShiftBit(1);
sr.ShiftBit(0);
sr.ShiftBit(1);
sr.Latch();

// Display for 1s
Thread.Sleep(1000);

// Write to all 8 registers with a byte value
// ShiftByte latches data by default
sr.ShiftByte(0b_1000_1101);

The following diagram demonstrates the required wiring for the Minimal pin mapping. In particular, OE must be wired to ground, and SRCLR must be wired high.

The following example demonstrates using additional features and requires different wiring.

Sn74hc595 sr = new(Sn74hc595PinMapping.Complete);

// Write to all 8 registers with a byte value
// ShiftByte latches data by default
sr.ShiftByte(0b_1000_1101);

// Display for 1s
Thread.Sleep(1000);

// disable output temporarily
sr.OutputEnable = false;

// Display for 1s
Thread.Sleep(1000);

// re-enable output
sr.OutputEnable = true;

// clear storage before writing new values
sr.ClearStorage();

// Light up three of first four LEDs
sr.ShiftBit(1);
sr.ShiftBit(1);
sr.ShiftBit(0);
sr.ShiftBit(1);
sr.Latch();

The following diagram demonstrates the required wiring for the Complete pin mapping.

If you want to use SPI, see the ShiftRegister binding, which includes more information on SPI.