The ATmegaS64M1 is the radiation tolerant version of the popular Microchip ATmega64M1 8-bit AVR microcontroller.
This high-performance, low-power Microchip 8-bit AVR RISC-based microcontroller combines 64KB ISP flash memory with read-while-write capabilities, 2KB EEPROM, 4KB SRAM, 27 general purpose I/O lines, 32 general purpose working registers, one motor power stage controller, two flexible timer/counters with compare modes and PWM, one UART with HW LIN, an 11-channel 10-bit A/D converter with two differential programmable gain input stages, a 10-bit D/A converter, a programmable watchdog timer with internal individual oscillator, SPI serial port, an on-chip debug system, and four software selectable power saving modes. 
By executing powerful instructions in a single clock cycle, the device achieves throughputs approaching 1 MIPS per MHz, balancing power consumption and processing speed.  With its CAN controller, power stage controller, ADC, DAC and analog comparators the ATmegaS64M1 microcontroller is a great choice for many of the most common space applications, which typically require a small footprint and low power. The device operates between 3-3.6 volts.

This space-qualified version of the product adds:  Ceramic & Hermetic packages, extended temperature range -55C to 125C, extended qualification flow equivalent to QML-V or QML-Q space grade.  Radiation performance for the ATmegaS64M1:  SEL LET > 60 MeV.cm2/mg (at 125C), and TID up to 30 Krad (Si).

• Core
• High-performance, Low-Power 8-bit AVR® Microcontroller
• Memories
• Data and Nonvolatile Program Memory
• 64K Bytes flash of in-system programmable program memory
• 2K Bytes of in-system programmable EEPROM
• 4K Bytes internal SRAM
• Peripherals
• CAN 2.0A/B with Six Message Objects - ISO16845 certified
• 8-bit UART (supporting LIN 2.1 and 1.3 controller)
• One 12-bit High-speed Power Stage Controller
• 11 channels 10-bit ADC
• 10-bit DAC
• Voltage
• Single supply voltage from 3.0V to 3.6V
• Temperature Range
• -55°C to 125°C
• Radiation Performances
• No Single Event Latch-up Below an LET Threshold of 60 MeV.cm2 /mg @125°C
• Total Ionizing Dose of 30 krad(Si)
• Packages
• 32-lead Ceramic Quad Flat package (CQFP)
• 32-lead Plastic Quad Flat package (TQFP)