ATMEGA644-20AU

The ATmega644 is a low-power CMOS 8-bit microcontroller based on the AVR enhanced RISC architecture. By executing powerful instructions in a single clock cycle, the ATmega644 achieves throughputs approaching 1 MIPS per MHz allowing the system designer to optimize power consumption versus processing speed. The AVR core combines a rich instruction set with 32 general purpose working registers. All the 32 registers are directly connected to the Arithmetic Logic Unit (ALU), allowing two independent registers to be accessed in one single instruction executed in one clock cycle. The resulting architecture is more code efficient while achieving throughputs up to ten times faster than conventional CISC microcontrollers. The ATmega644 provides the following features: 64 Kbytes of In-System Programmable Flash with Read-While-Write capabilities, 2 Kbytes EEPROM, 4 Kbytes SRAM, 32 general purpose I/O lines, 32 general purpose working registers, Real Time Counter (RTC), three flexible Timer/Counters with compare modes and PWM, 2 USARTs, a byte oriented 2-wire Serial Interface, a 8-channel, 10-bit ADC with optional differential input stage with programmable gain, programmable Watchdog Timer with Internal Oscillator, an SPI serial port, IEEE std. 1149.1 compliant JTAG test interface, also used for accessing the On-chip Debug system and programming and six software selectable power saving modes. The Idle mode stops the CPU while allowing the SRAM, Timer/Counters, SPI port, and interrupt system to continue functioning. The Power-down mode saves the register contents but freezes the Oscillator, disabling all other chip functions until the next interrupt or Hardware Reset. In Power-save mode, the asynchronous timer continues to run, allowing the user to maintain a timer base while the rest of the device is sleeping. The ADC Noise Reduction mode stops the CPU and all I/O modules except Asynchronous Timer and ADC, to minimize switching noise during ADC conversions. In Standby mode, the Crystal/Resonator Oscillator is running while the rest of the device is sleeping. This allows very fast start-up combined with low power consumption. In Extended Standby mode, both the main Oscillator and the Asynchronous Timer continue to run. The device is manufactured using Atmel’s high-density nonvolatile memory technology. The Onchip ISP Flash allows the program memory to be reprogrammed in-system through an SPI serial interface, by a conventional nonvolatile memory programmer, or by an On-chip Boot program running on the AVR core. The boot program can use any interface to download the application program in the application Flash memory. Software in the Boot Flash section will continue to run while the Application Flash section is updated, providing true Read-While-Write operation. By combining an 8-bit RISC CPU with In-System Self-Programmable Flash on a monolithic chip, the Atmel ATmega644 is a powerful microcontroller that provides a highly flexible and cost effective solution to many embedded control applications.

Key features

• High-performance, Low-power Atmel AVR 8-bit Microcontroller
• Advanced RISC Architecture – 131 Powerful Instructions – Most Single-clock Cycle Execution – 32x8 General Purpose Working Registers – Fully Static Operation – Up to 20 MIPS Throughput at 20MHz
• High Endurance Non-volatile Memory segments – 64 Kbytes of In-System Self-programmable Flash program memory – 2 Kbytes EEPROM – 4 Kbytes Internal SRAM – Write/Erase cyles: 10,000 Flash/100,000 EEPROM – Data retention: 20 years at 85℃/100 years at 25℃ – Optional Boot Code Section with Independent Lock Bits In-System Programming by On-chip Boot Program True Read-While-Write Operation – Programming Lock for Software Security
• JTAG (IEEE std. 1149.1 Compliant) Interface – Boundary-scan Capabilities According to the JTAG Standard – Extensive On-chip Debug Support – Programming of Flash, EEPROM, Fuses, and Lock Bits through the JTAG Interface
• Peripheral Features – Two 8-bit Timer/Counters with Separate Prescalers and Compare Modes – One 16-bit Timer/Counter with Separate Prescaler, Compare Mode, and Capture Mode – Real Time Counter with Separate Oscillator – Six PWM Channels – 8-channel, 10-bit ADC Differential mode with selectable gain at 1x, 10x or 200x – Byte-oriented Two-wire Serial Interface – One Programmable Serial USART – Master/Slave SPI Serial Interface – Programmable Watchdog Timer with Separate On-chip Oscillator – On-chip Analog Comparator – Interrupt and Wake-up on Pin Change
• Special Microcontroller Features – Power-on Reset and Programmable Brown-out Detection – Internal Calibrated RC Oscillator – External and Internal Interrupt Sources – Six Sleep Modes: Idle, ADC Noise Reduction, Power-save, Power-down, Standby and Extended Standby
• I/O and Packages – 32 Programmable I/O Lines – 40-pin PDIP, 44-lead TQFP, and 44-pad QFN/MLF
• Speed Grades – ATmega644V: 0 - 4MHz @ 1.8V - 5.5V, 0 - 10MHz @ 2.7V - 5.5V – ATmega644: 0 - 10MHz @ 2.7V - 5.5V, 0 - 20MHz @ 4.5V - 5.5V
• Power Consumption at 1MHz, 3V, 25℃ – Active: 240μA @ 1.8V, 1MHz – Power-down Mode: 0.1μμ @ 1.8V