This commands scans for ISO 14443-3 (Type A) compliant PICCs in the field of the antenna.

If the ReqAll parameter flag is set, both PICCs in idle state and PICCs in halt state will be switched to ready state. If this flag is not set, only PICCs in idle state will be switched to ready state.

Only PICCs in ready state may be selected via the Iso14a.Select command.

This command covers the commands REQA and WAKE-UP as specified by the ISO 14443-3 standard.


Parameters (request frame)

Name Type/Size Description
- Bit mask (8 bits) -
RFU Integer (bit mask area 0xFE) Zero padding
ReqAll Boolean (bit 0x01) If enabled, all PICCs (even those in halt state) will be requested.

Returned values (response frame)

Name Type/Size Description
ATQA Bit mask (16 bits) Answer to request of type A (ATQA), according to the ISO 14443-3 standard.
UIDSize Enumeration (bit mask area 0xC000) Length of "Unique IDentifier" (UID). The UID may be either a fixed number or a number generated randomly by the PICC (and therefore not unique!).
  • SingleSize (0x00)
    UID length of 4 Bytes.
  • DoubleSize (0x01)
    UID length of 7 Bytes.
  • TripleSize (0x02)
    UID length of 10 Bytes.
RFU Integer (bit 0x2000) Zero padding
Coll Integer (bit mask area 0x1F00) If not 0, two or more PICCs of different types are present in the HF field of the reader. In this case, the selection PICC procedure can be carried out normally with the Iso14a.Select command.
Coding Integer (bit mask area 0x00FF) Card-specific coding
Collision Boolean (8 bits) True if an Collision was detected