i am a new user on arduino card. i have a question about "Pro Micro with Atmega32U4". - is this product programmable several times ? and the third pin (RST) - (Reset). so, does reset mean it erases memory?
Thank you in advance for your answers.
Yes, the microcontroller on Arduinos (in this case the Atmega32U4) can be reprogrammed many times, only limited by the write limit of the flash memory (As I remember Microchip garantuees about 100,000 write cycles at minimum). You can program it over the USB port of the board or through an ISP programmer.
The Reset pin will do the same as a power cycle (turning off an on again) would do. If you program the Arduino, this program will start, when the Arduino get's power (after the Bootloader, which is used to program over USB without ISP programmer). This program will then run until the power is turned off, or until a reset is done by pulling the RST pin to ground. When the RST pin is released again, the Arduino will again start up. The flash memory and the EEPROM stay untouched and will not loose any data. But the data, that lies in SRAM (like any normal variable in the program) will be lost.