ATMEGA644P-20MU

ATmega644P-20MU is an 8‑bit AVR microcontroller (from Atmel/Microchip) with 64 KB flash, 4 KB RAM, and 2 KB EEPROM. It uses the AVR RISC core and can run up to 20 MHz. The -20MU suffix mainly denotes a 20 MHz max clock and a surface-mount package (MU).
Key peripherals and features:
- Serial: 2 USARTs, plus SPI and I2C (TWI)
- ADC: 8-channel, 10-bit
- Timers: three timers (two 8-bit, one 16-bit) with PWM and input capture
- Peripherals: analog comparator, watchdog timer, brown‑out detector, external/pin-change interrupts
- Programming: in-system programming via SPI
- Power: operates over a broad supply range (voltage depends on frequency)
Typical uses:
- Embedded control, data acquisition, small hobby/robotics projects
- Applications needing moderate program memory, multiple serial interfaces, and ADC input
Development tools: AVR-GCC, Microchip Studio, avrdude; broad community and example code available.

Equivalent devices in the AVR megaAVR family with similar 64 KB flash include:
- ATmega644P (other package variants, e.g., ATmega644P in different suffixes)
- ATmega645 (64K-class family member)
Also potential alternatives (different memory/I/O):
- ATmega1284P (more memory)
- ATmega324P or ATmega32 (less memory)
Note: exact pinouts and peripherals differ, so check package and I/O compatibility for a drop‑in replacement.

Here are the key features of ATMEGA644P-20MU (44-pin TQFP):
- 8-bit AVR RISC CPU, single-cycle instruction, up to 20 MHz operation
- Power supply: 2.7–5.5 V (speed grade 20 MHz at upper voltage)
- Memory: 64 KB Flash, 8 KB SRAM, 4 KB EEPROM
- I/O: ~32 general-purpose I/O lines (Ports B, C, D)
- Analog: 8-channel 10-bit ADC with multiplexer; analog comparator
- Timers: Timer0 (8-bit PWM), Timer1 (16-bit), Timer2 (8-bit PWM)
- PWM: multiple PWM outputs across timers
- Communications: USART, SPI, Two-Wire Interface (I2C/TWI)
- Debug/Programming: In-System Programming (ISP); JTAG interface on Port C (enabled via fuse)
- Peripherals: Watchdog Timer, brown-out detector, multiple sleep modes for low power
- Package: 44-pin TQFP (MU)
These make it suitable for embedded control tasks requiring moderate memory, rich I/O, and multiple communication interfaces.

- Pin count: 44 pins (TQFP-44) in the MU package.
- Function: 8-bit AVR microcontroller (ATmega644P) with 64 KB flash, 4 KB SRAM, 2 KB EEPROM; peripherals include three timers (Timer0/1/2), 8-channel 10-bit ADC, USART, SPI, I2C/TWI, PWM outputs, and watchdog. Operates up to 20 MHz.

Manufacturer: Microchip Technology Inc. It is an American multinational semiconductor company that designs and manufactures microcontrollers (including AVR), memory, and analog ICs. It was formerly Atmel and was acquired by Microchip in 2016; headquarters in Chandler, Arizona.

Key application areas for ATmega644P-20MU:
- General-purpose embedded control in low- to mid-complexity systems
- Industrial automation and process control (sensor interfacing, I/O expansion)
- Home automation, appliances, and smart devices
- Robotics and motor control (PWM, timers, ADC channels)
- Data acquisition, instrumentation, and portable measurement equipment
- Embedded data logging and monitoring systems
- Consumer electronics (dashboards, displays, audio/light controllers)
- Education and hobbyist platforms (ease of AVR development)

ATmega644P-20MU is in a 44-pin LQFP (Thin Quad Flat Pack) package. The MU suffix denotes this LQFP package.