Create a complete new schematic and PCB-ready design for a single-channel Universal I/O controller based on an ATmega328 microcontroller. Core requirement: Design a new circuit from scratch. Do not reuse or include LM76202QPWPRQ1, AD7708, HC595, CD4066, LM2902, or other external switching/ADC/control ICs unless absolutely required and explicitly approved. The ATmega328 should directly measure and control the universal I/O as much as practical. Universal Input requirements: The same field input connector must support software-configurable modes: 1. Digital input 2. Analog voltage input 3. 0–10 V input 4. 0–20 mA input 5. Resistance measurement 6. RTD measurement: PT1000 and NI1000 7. Thermistor measurement: 10k Type II and 10k Type III Universal Output requirements: Provide a software-configurable universal output from the ATmega328. Include at minimum: 1. Digital output 2. PWM-based analog voltage output using filtering/buffering if needed 3. Clearly document whether true 0–10 V output or 0–20 mA output is supported directly, requires extra circuitry, or is out of scope for the first revision. Architecture constraints: - Use ATmega328 ADC pins directly for measurements. - Avoid HC595 shift registers. - Avoid CD4066 analog switches. - Avoid LM76202 protection IC. - Avoid AD7708 external ADC. - Prefer simple discrete protection, resistor dividers, shunt resistors, RC filters, jumpers or low-cost analog selection methods if needed. - Use clear ALL_CAPS net names. - Design for a 24 V industrial field environment where possible, but keep MCU pins protected within safe voltage/current limits. Expected schematic blocks: 1. Power input and regulation for ATmega328 logic rail. 2. ATmega328 core: power pins, reset, clock option, ISP/programming header, decoupling. 3. Universal input field connector with protection. 4. 0–10 V divider path into ADC. 5. 0–20 mA shunt path into ADC. 6. Resistance/RTD/thermistor divider or excitation path into ADC. 7. Digital input threshold/protection path into an ATmega328 GPIO. 8. Universal output connector with digital/PWM output conditioning. 9. Optional test points and calibration notes. Implementation expectations: - Select suitable components from the Flux library. - Add all required resistors, capacitors, connectors, protection parts, regulator, and ATmega328 support parts. - Wire the complete schematic. - Add Role and Role Details properties to important parts. - Run ERC and fix schematic errors. - Create a project document explaining the circuit architecture, mode configuration table, ATmega328 pin mapping, ADC scaling equations, firmware configuration notes, and limitations. - After schematic validation, set up a reasonable PCB board size and stackup, place components by functional block, and prepare for routing. Important design notes: - Because the ATmega328 has limited ADC resolution and input range, include scaling and protection so all field signals are reduced to the MCU ADC range. - Firmware must select the measurement mode and apply calibration/scaling formulas. - If fully software-selectable mode switching cannot be achieved without extra analog-switch ICs, propose a simple alternative such as jumpers, resistor option links, MOSFET/discrete switching, or separate input terminals, and document the tradeoff before implementation.