The **DSO-CSS-R2** is a compact, open-source digital storage oscilloscope (DSO) kit designed primarily for educational purposes and hobbyists. It is based on the STM32 microcontroller architecture and utilizes a cost-effective design to provide basic signal visualization. --- ### Core Electronic Components The hardware architecture of the DSO-CSS-R2 is divided into three main functional blocks: the **Analog Front-End**, the **Processing Core**, and the **User Interface**. #### 1. Analog Front-End (Signal Conditioning) Before the signal reaches the microcontroller, it must be scaled and shifted to fit the input range (typically 0V to 3.3V). * **Operational Amplifiers (Op-Amps):** Usually features chips like the **TL084** or **TL072**. These are used for impedance matching (high input impedance) and gain adjustment. * **Coupling Circuit:** Includes capacitors and switches to toggle between **AC** (removes DC offset) and **DC** (shows full signal) modes. * **Voltage Dividers:** Resistor networks used to attenuate high-voltage signals so they don't damage the MCU. #### 2. Processing Core (The "Brain") * **Main MCU:** Typically powered by an **STM32F103C8T6** (ARM Cortex-M3). * **ADC (Analog-to-Digital Converter):** The STM32's internal 12-bit ADC converts the conditioned analog voltage into digital data. * **DMA (Direct Memory Access):** Used to move data from the ADC to the RAM at high speeds without taxing the CPU. * **Clock Crystal:** An 8MHz crystal (usually multiplied internally to 72MHz) provides the timing for sampling rates. #### 3. User Interface & Power * **Display:** A 2.4-inch TFT LCD (often driven by the **ILI9341** controller) via an 8-bit or SPI interface. * **Rotary Encoders/Buttons:** Used to adjust timebase (s/div), sensitivity (V/div), and trigger levels. * **Power Management:** Uses linear regulators (e.g., **78L05** or **AMS1117-3.3**) to provide stable voltages to the analog and digital rails. --- ### Technical Specifications Table | Feature | Specification (Approximate) | | :--- | :--- | | **Max Real-time Sampling Rate** | 1Msps | | **Analog Bandwidth** | 0 - 200KHz | | **Sensitivity Range** | 10mV/Div - 5V/Div | | **Input Impedance** | 1MΩ | | **Resolution** | 12 bits | | **Record Length** | 1024 points | | **Power Supply** | 9V DC (8V - 12V) | --- ### Circuit Board Characteristics The R2 (Revision 2) often features improvements over the original DSO138 or earlier CSS models: 1. **SMD Pre-soldered:** Most versions come with the STM32 and small surface-mount components already soldered to prevent assembly errors. 2. **Analog/Digital Ground Separation:** Improved PCB layout to reduce noise interference from the digital display onto the analog signal trace. 3. **BNC Connector:** Standardized input for professional oscilloscope probes (1x/10x). ---