- // SELECT_ALL
- ReaderTransmit(sel_all, sizeof(sel_all), NULL);
- if (!ReaderReceive(resp, resp_par)) return 0;
-
- if (Demod.collisionPos) { // we had a collision and need to construct the UID bit by bit
- memset(uid_resp, 0, 4);
- uint16_t uid_resp_bits = 0;
- uint16_t collision_answer_offset = 0;
- // anti-collision-loop:
- while (Demod.collisionPos) {
- Dbprintf("Multiple tags detected. Collision after Bit %d", Demod.collisionPos);
- for (uint16_t i = collision_answer_offset; i < Demod.collisionPos; i++, uid_resp_bits++) { // add valid UID bits before collision point
- uint16_t UIDbit = (resp[i/8] >> (i % 8)) & 0x01;
- uid_resp[uid_resp_bits / 8] |= UIDbit << (uid_resp_bits % 8);
+ if (anticollision) {
+ // SELECT_ALL
+ ReaderTransmit(sel_all, sizeof(sel_all), NULL);
+ if (!ReaderReceive(resp, resp_par)) return 0;
+
+ if (Demod.collisionPos) { // we had a collision and need to construct the UID bit by bit
+ memset(uid_resp, 0, 4);
+ uint16_t uid_resp_bits = 0;
+ uint16_t collision_answer_offset = 0;
+ // anti-collision-loop:
+ while (Demod.collisionPos) {
+ Dbprintf("Multiple tags detected. Collision after Bit %d", Demod.collisionPos);
+ for (uint16_t i = collision_answer_offset; i < Demod.collisionPos; i++, uid_resp_bits++) { // add valid UID bits before collision point
+ uint16_t UIDbit = (resp[i/8] >> (i % 8)) & 0x01;
+ uid_resp[uid_resp_bits / 8] |= UIDbit << (uid_resp_bits % 8);
+ }
+ uid_resp[uid_resp_bits/8] |= 1 << (uid_resp_bits % 8); // next time select the card(s) with a 1 in the collision position
+ uid_resp_bits++;
+ // construct anticollosion command:
+ sel_uid[1] = ((2 + uid_resp_bits/8) << 4) | (uid_resp_bits & 0x07); // length of data in bytes and bits
+ for (uint16_t i = 0; i <= uid_resp_bits/8; i++) {
+ sel_uid[2+i] = uid_resp[i];
+ }
+ collision_answer_offset = uid_resp_bits%8;
+ ReaderTransmitBits(sel_uid, 16 + uid_resp_bits, NULL);
+ if (!ReaderReceiveOffset(resp, collision_answer_offset, resp_par)) return 0;