keyestudio leonardo r3 microcontroller development board with usb cable kit for arduino project keyestudio <b>specification</b><br> controller: atmega32u4<br> working frequency: 16 mhz<br> working voltage: 5v<br> input voltage (recommended): 7-12v<br> digital i/o port: 23<br> pwm channel: 7<br> analog input: 12<br> maximum allowable current of 5v digital/analog port: 40 ma<br> maximum allowable current of 3.3v digital/analog port: 50 ma<br> flash memory: 32 kb (atmega32u4) of which 4 kb used by boot loader<br> sram: 2.5 kb (atmega32u4)<br> eeprom: 1 kb (atmega32u4)<br> <br> <b>other related instructions</b><br> digital io port: 23 (d0 - d13, d14-miso, d15-sck, d16-mosi, d18-23 [a0-a5])<br> analog input: 12 (a0 - a5, d4 - a6, d6 - a7, d8 - a8, d9 - a9, d10 - a10, d12-a11)<br> serial communication: d0 (rx) and d1 (tx)<br> iic communication: d2 (sda) and d3 (scl)<br> external interrupt: d3 (interrupt 0), d2 (interrupt 1), d0 (interrupt 2), d1 (interrupt 3) and d7 (interrupt 4)<br> pwm port: d3, d5, d6, d9, d10, d11 and d13<br> spi: icsp pins.support spi communication by using the spi library. it is important to note that spi pins do not connect to any number i/o pins like uno, they can only work on the icsp port.this <br>means that if your expansion board has no icsp pin connected to the 6 feet, it will not work.<br> led: 13. there is a built-in led on the digital pin 13. when the pins are high level, led is bright;when the pins are low level,the led is not bright.<br> <br> <b>list:</b><br> 1 x keyestudio leonardo r3 development board <br> 1 x usb cable<br>