Open Session and Deselect in Android Studio

[andre2]

Posted on August 11, 2015 at 12:12

Hi,

I'm using the M24SR Discovery Board and I'm having some trouble when I want to communicate with the board via NFC. I'm trying to open a RF session with my Smartphone so that the GPO of the M24SR is driven low. Then I want to read some values out of the EEPROM and after that I want to close the session again (Deselect). Sounds easy, but I really do not get it how to send the right command for open session and deselect. My other code looks like this: //Select NFC T4 application                     iso.transceive(global.getT4select());                     //Select NDEF file                     iso.transceive(global.getNDEFselect());                     //Verify the Read password                     pw = iso.transceive(global.getVerify_read());                     if(pw[0] == global.check_string[0] && pw[1] == global.check_string[1] ) {                         /*Read beyond NDEF message*/                         //Read temperature                         temp = iso.transceive(new byte[]{(byte) 0xA2, (byte) 0xB0, 0x00, (byte) 0x80, 0x04});                         //Read operating hours                         time = iso.transceive(new byte[]{(byte) 0xA2, (byte) 0xB0, 0x00, (byte) 0x84, 0x04}); } All of the commands are working well, but I do not know how to code the open session and deselect command. I hope you can help me! Andre

[France Berthelot · Accepted solution]

Posted on August 23, 2016 at 18:16

Hi,

When the GPO is configured as State Control, the I2C or RF host can control the state of the GPO by sending a dedicated command. During an RF or I2C session, the M24SR can control the GPO pin. After receiving a valid Set GPO command, GPO pin is driven low. GPO will be released after a valid Reset command or after a Power off. Here the cmd: // use to drive GPO pins to low or to HZ  static final byte[] m24sr7816STStateCtrlcmd = new byte[]{                                                                 (byte) 0xA2,(byte) 0xD6, // CAS , INS                                                                 (byte) 0x00,(byte) 0x1F, // P1  , P2                                                                 (byte) 0x01,(byte) 0x00  // LC, DATA_1                                                             }; With if (setStateHz) // true is {     cmd[DATA1_INDEX] = (byte) 0x01; } else {     cmd[DATA1_INDEX] = (byte) 0x00; }

Before sending this command, the system file shall be selected by issuing the System

Select command. Apologize for delay answer. Regards