ATMEGA2561-16AU

The ATMEGA2561-16AU from Microchip (formerly Atmel) is a high-performance 8-bit AVR RISC microcontroller featuring 256KB of in-system programmable Flash memory, the largest in the ATmega product family. The 256KB Flash provides ample code space for complex applications including RTOS-based systems, communication protocol stacks, and data logging algorithms. The 8KB SRAM supports extensive data buffering and variable storage, while the 4KB EEPROM provides non-volatile storage for calibration data, configuration parameters, and device settings. The ATMEGA2561 provides 54 general-purpose I/O lines, each with individually selectable pull-up resistors and interrupt-on-change capability, providing maximum flexibility in pin assignment. The 10-bit ADC with 16 channels and differential input mode supports a wide range of sensor interfaces including thermocouples, strain gauges, and pressure sensors. Two USARTs, two SPI ports, and one I2C (TWI) interface provide multiple simultaneous communication channels for connecting to displays, sensors, memory cards, and other MCUs. The six flexible timers/counters include four 16-bit timers with PWM generation, input capture, and output compare capabilities, making the device suitable for motor control and power electronics applications. The JTAG interface provides full-speed in-circuit debugging and Flash programming without using any on-chip resources. The ATMEGA2561 is code-compatible with all other ATmega devices, enabling easy migration from smaller ATmega parts as application requirements grow.

The ATMEGA2561-16AU operates as an 8-bit AVR RISC microcontroller. Key subsystems include: (1) AVR Core – a Harvard-architecture 8-bit RISC processor with 32 x 8-bit general-purpose registers; most instructions execute in a single clock cycle at 16MHz (16 MIPS throughput); the 2-stage pipeline (fetch + execute) enables single-cycle execution; the MCU supports 133 powerful instructions including 32×8 hardware multiply; (2) Memory – 256KB Flash organized as 128K x 16-bit words; 8KB SRAM accessed in 2 cycles; 4KB EEPROM with 100,000 erase/write cycle endurance; external memory interface (XMEM) supports up to 64KB external SRAM; (3) I/O Ports – 54 I/O pins organized into 7 ports (PORTA-PORTG); each pin has a data register, direction register, and pull-up resistor control; pins can generate pin-change interrupts on any edge; PORTA also serves as the external memory interface address/data bus; (4) ADC – a 10-bit successive-approximation ADC with 15-260us conversion time; 16 single-ended or differential input channels; programmable gain stage (1x, 10x, 200x) for differential measurements; auto-trigger mode from timer compare match; free-running mode for continuous conversion; (5) JTAG – a standard IEEE 1149.1 JTAG interface for boundary-scan testing and in-system programming; the JTAG interface also provides a debug access port (DAP) for real-time breakpoints and single-step debugging without using on-chip resources.

• Industrial controller: 54 I/O for multiple relay/solenoid outputs and sensor inputs, 256KB Flash for control algorithms, dual USART for Modbus communication
• Motor controller: 4x 16-bit PWM timers for multi-axis motor control, ADC for current/voltage feedback, 8KB SRAM for FOC calculations
• Data logger: 256KB Flash for data storage, EEPROM for configuration, dual SPI for SD card and sensor, 8KB SRAM for data buffering