Grove 125Khz RFID won't work with SoftSerial/seeeduino lite

I have this gorve RFID reader: … -1008.html
and this seeduino lite based on 32U4

the RFID reader is set in UART mode.
If I connect to software serial with 10 as RX, 11 as TX, I got nothing. code as below:
#include <SoftwareSerial.h>

SoftwareSerial mySerial(10, 11); // RX, TX

void setup()
// Open serial communications and wait for port to open:
while (!Serial) {
; // wait for serial port to connect. Needed for Leonardo only

// set the data rate for the SoftwareSerial port


void loop() // run over and over
if (mySerial.available())
if (Serial.available())

But, if I connect RFID to serial1, I got the reading, code as following:

static long baud = 9600;
void setup() {
//pinMode(DTR_PIN, OUTPUT);
//digitalWrite(DTR_PIN, LOW);
// while the serial stream is not open, do nothing:
while (!Serial) ;

void loop() {
// copy from virtual serial line to uart and vice versa
if (Serial.available()) {
char c = (char);
if (Serial1.available()) {
char c = (char);


what is wrong?

BTW, I have tested both code with my grove GPS on software serial and seria1 on the same seeeduino lite, but send correct data.

Why my grove 125Khz RFID can not work with softserial?


Could you please post more details of your setup – photos of your setup, Arduino IDE version, connection diagram and RFID tag that was used.

Thanks and Warm Regards.