+
+static void iso14a_set_ATS_times(uint8_t *ats) {
+
+ uint8_t tb1;
+ uint8_t fwi, sfgi;
+ uint32_t fwt, sfgt;
+
+ if (ats[0] > 1) { // there is a format byte T0
+ if ((ats[1] & 0x20) == 0x20) { // there is an interface byte TB(1)
+ if ((ats[1] & 0x10) == 0x10) { // there is an interface byte TA(1) preceding TB(1)
+ tb1 = ats[3];
+ } else {
+ tb1 = ats[2];
+ }
+ fwi = (tb1 & 0xf0) >> 4; // frame waiting time integer (FWI)
+ if (fwi != 15) {
+ fwt = 256 * 16 * (1 << fwi); // frame waiting time (FWT) in 1/fc
+ iso14a_set_timeout(fwt/(8*16));
+ }
+ sfgi = tb1 & 0x0f; // startup frame guard time integer (SFGI)
+ if (sfgi != 0 && sfgi != 15) {
+ sfgt = 256 * 16 * (1 << sfgi); // startup frame guard time (SFGT) in 1/fc
+ NextTransferTime = MAX(NextTransferTime, Demod.endTime + (sfgt - DELAY_AIR2ARM_AS_READER - DELAY_ARM2AIR_AS_READER)/16);
+ }
+ }
+ }
+}
+
+
+static int GetATQA(uint8_t *resp, uint8_t *resp_par) {
+
+#define WUPA_RETRY_TIMEOUT 10 // 10ms
+ uint8_t wupa[] = { 0x52 }; // 0x26 - REQA 0x52 - WAKE-UP
+
+ uint32_t save_iso14a_timeout = iso14a_get_timeout();
+ iso14a_set_timeout(1236/(16*8)+1); // response to WUPA is expected at exactly 1236/fc. No need to wait longer.
+
+ uint32_t start_time = GetTickCount();
+ int len;
+
+ // we may need several tries if we did send an unknown command or a wrong authentication before...
+ do {
+ // Broadcast for a card, WUPA (0x52) will force response from all cards in the field
+ ReaderTransmitBitsPar(wupa, 7, NULL, NULL);
+ // Receive the ATQA
+ len = ReaderReceive(resp, resp_par);
+ } while (len == 0 && GetTickCount() <= start_time + WUPA_RETRY_TIMEOUT);
+
+ iso14a_set_timeout(save_iso14a_timeout);
+ return len;
+}
+
+