Arduino's MKRZero brings users the power of a Zero in the smaller format established by the MKR form factor. The MKRZero board is a great educational tool for learning about 32-bit application development. It has an on-board SD connector with dedicated SPIs that allows users to interact with music files using the Arduino Sound library and I2S library with no extra hardware. The board is powered by Microchip�s SAM D21 MCU, which features a 32-bit Arm� Cortex� -M0+ core operating at 3.3 V logic levels. The board contains everything needed to support the microcontroller; simply connect it to a computer with a micro-USB cable or power it by a LiPo battery. The battery voltage can also be monitored since a connection between the battery and the analog converter of the board exists and the board includes charge circuitry to easily recharge the LiPo from a 5 V source.

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Tech specs

 

Miicrocontroller	SAMD21 Cortex-M0+ 32bit low power ARM® MCU
Board Power Supply (USB/VIN)	5V
Supported Battery(*)	Li-Po single cell, 3.7V, 700mAh minimum
DC Current for 3.3V Pin	600mA
DC Current for 5V Pin	600mA
Circuit Operating Voltage	3.3V
Digital I/O Pins	22
PWM Pins	12 (0, 1, 2, 3, 4, 5, 6, 7, 8, 10, A3 - or 18 -, A4 -or 19)
UART	1
SPI	1
I2C	1
Analog Input Pins	7 (ADC 8/10/12 bit)
Analog Output Pins	1 (DAC 10 bit)
External Interrupts	10 (0, 1, 4, 5, 6, 7, 8, A1 -or 16-, A2 - or 17)
DC Current per I/O Pin	7 mA
Flash Memory	256 KB
Flash Memory for Bootloader	8 KB
SRAM	32 KB
EEPROM	no
Clock Speed	32.768 kHz (RTC), 48 MHz
LED_BUILTIN	32