@gleon said in UHF RFID on a M5Core2: Hi! I’ve been trying to compile the demo sketch for multiple reads. With some tweaking I was able to compile the demo single read sketch... But i have not been able to compile the multiple read. I've switched the library: #include <M5Core2.h> and also the ports for the serial comm: Serial2.begin(115200, SERIAL_8N1, 33, 32); But i could not make the multiple read sketch to compile. Actually, not sure if I'm having problems with this part of the code: RFID.Set_transmission_Power(2600); RFID.Set_the_Select_mode(); RFID.Delay(100); RFID.Readcallback(); RFID.clean_data(); or this one: cards = RFID.Multiple_polling_instructions(6); for (size_t i = 0; i < cards.len; i++) { if(cards.card[i]._EPC.length() == 24) { Serial.println("RSSI :" + cards.card[i]._RSSI); Serial.println("PC :" + cards.card[i]._PC); Serial.println("EPC :" + cards.card[i]._EPC); Serial.println("CRC :" + cards.card[i]._CRC); } } Serial.println(" "); RFID.clean_data(); Does anyone have aby thoughts on where to problem could be? Gleon, What Sketch do you use? You can't see EPC or Aton Lite or Core2 Thank s