## Technical Overview: MC14094BDR2G The **MC14094BDR2G** is a high-voltage CMOS 8-stage shift/store bus register. It consists of an 8-bit shift register and an 8-bit latch with 3-state parallel outputs. This device is commonly used for serial-to-parallel data conversion and as an output expander for microcontrollers. --- ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Logic Type** | Shift Register (Serial-to-Parallel) | | **Number of Stages** | 8 Bits | | **Supply Voltage (Vdd)** | 3.0V to 18V | | **Output Type** | 3-State (Tri-state) | | **Package Type** | SOIC-16 (Small Outline Integrated Circuit) | | **Operating Temperature** | -55°C to +125°C | | **Propagation Delay** | 150 ns @ 10V (Typical) | --- ### 2. Pin Configuration and Functions The device uses a 16-pin layout. Below are the critical functional pins: * **Data (Pin 2):** Serial data input. * **Clock (Pin 3):** Data is shifted on the positive-going transition of the clock. * **Strobe (Pin 1):** When HIGH, data from the shift register is transferred to the storage latches. * **Output Enable (Pin 15):** When HIGH, the 8-bit parallel outputs are active. When LOW, they are in a high-impedance state (Hi-Z). * **QS & Q'S (Pins 9 & 10):** Serial outputs used for cascading multiple chips to create 16, 24, or 32-bit registers. * **Q1 - Q8 (Pins 4-7, 11-14):** The 8 parallel data outputs. --- ### 3. Functional Block Description The MC14094BDR2G operates in two primary stages: 1. **Shift Register Stage:** Data enters serially through the **Data** pin. With every **Clock** pulse, the bit moves one position down the register. 2. **Storage Latch Stage:** Once the 8 bits are loaded, a pulse on the **Strobe** pin moves all 8 bits simultaneously into the storage latches. This prevents the outputs from flickering while the data is being shifted in. --- ### 4. Code Example: Arduino Interface The following snippet demonstrates how to send an 8-bit number to the MC14094BDR2G using standard SPI-like logic. ```cpp const int dataPin = 11; // To Pin 2 (Data) const int clockPin = 13; // To Pin 3 (Clock) const int strobePin = 10; // To Pin 1 (Strobe) void writeToRegister(byte data) { // Pull strobe LOW so outputs don't change while shifting digitalWrite(strobePin, LOW); // Shift out the bits (MSB first) shiftOut(dataPin, clockPin, MSBFIRST, data); // Pull strobe HIGH to update the parallel outputs digitalWrite(strobePin, HIGH); } ``` --- ### 5. Common Applications * **I/O Expansion:** Increasing the number of output pins on a microcontroller. * **LED Matrix Drivers:** Controlling rows or columns of LEDs. * **Industrial Controls:** Interfacing with high-voltage logic (up to 18V). * **Remote Control Serial-to-Parallel:** Converting long-distance serial signals into local parallel commands.