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.