Model: Adafruit Assembled Data Logging shield SD card interface: FAT16 or FAT32 Onboard regulator: 3.3 V Real time clock (RTC) keeps the time going even when the Arduino is unplugged
ATmega328p @ 8MHz with 3.3V logic/power 3.3V regulator with 500mA peak current output USB serial converter (CP2104) USB bootloader and serial port debugging Hardware I2C, hardware SPI support
Model: Adafruit Feather 32u4 Bluefruit LE Light as a (large?) feather ?? 5.7 grams ATmega32u4 @ 8MHz with 3.3V logic/power 3.3V regulator with 500mA peak current output
ATSAMD21G18 @ 48MHz with 3.3V logic/power 256KB of FLASH + 32KB of RAM 3.3V regulator with 500mA peak current output USB bootloader and serial port debugging Built-in 100mA lipoly charger with charging status indicator LED
ATSAMD21G18 @ 48MHz with 3.3V logic/power 256KB of FLASH + 32KB of RAM 3.3V regulator with 500mA peak current output USB bootloader and serial port debugging Built-in 100mA lipoly charger with charging status indicator LED
ATSAMD21G18 @ 48MHz with 3.3V logic/power 256KB of FLASH + 32KB of RAM 32.768 KHz crystal for clock generation & RTC 3.3V regulator with 500mA peak current output Comes with a USB bootloader and serial port debugging
ATSAME51 32-bit Cortex M4 core with 120 MH 32-bit, 3.3 V logic and power 512 KB Flash, 192 KB RAM 2 MB SPI FLASH chip 3.3V regulator with 500mA peak current output USB Type-C
ARM Cortex M4F (with HW floating point acceleration) running at 64MHz 1MB flash and 256KB SRAM Native Open Source USB stack??? pre-programmed with UF2 bootloader Bluetooth Low Energy compatible 2.4GHz radio FCC / IC / TELEC certified module
