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tutorials:products:rfidnfc:faqs.html [2012/07/23 18:42]
ktownsend
tutorials:products:rfidnfc:faqs.html [2016/01/28 18:05] (current)
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-====== ​Frequently Asked Questions  ​======+====== ​Moved! ​======
  
-Blah blah blah +This tutorial has moved to [[http://learn.adafruit.com/adafruit-pn532-rfid-nfc|http://​learn.adafruit.com/​adafruit-pn532-rfid-nfc]]
- +
-===== Can I set a delay calling readPassiveTargetID() ?  ===== +
- +
-readPassiveTargetID() intentionally waits around in a blocking delay until a card enters the magnetic field. ​ The reason for this blocking delay is to ensure a well-understood command/response flow Once the magnetic field is activated and a read request is sent via readPassiveTargetID,​ you can keep sending new commands to the PN532, but the moment a card or tag enters the field, the PN532 will send a response to the initial read request, even if it's in the middle of some other response or activity To avoid having to debug this in SW, a blocking delay was implemented to keep the command/response pattern as clear as possible. +
- +
-As a workaround to this blocking-delay limitation, an optional timeout was added to the latest NFC libraries to allow you to set a specific timeout after read requests. +
- +
-By default, the PN532 will wait forever for a card to enter the field By specifying a fixed number of retries via MxRtyPassiveActivation (see UM section 7.3.1 describing the **RFConfiguration** register, specifically CfgItem 5) the PN532 will abort the read request after specified number of attempts, and you can safely send new commands without worrying about mixing up response frames. ​ To wait forever, set MxRtyPassiveActivation to 0xFF.  To timeout after a fixed number of retries, set MxRtyPassiveActivation to anything less than 0xFF. +
- +
-Example Code: +
- +
-ToDo+
/home/ladyada/public_html/wiki/data/attic/tutorials/products/rfidnfc/faqs.html.1343068957.txt.gz · Last modified: 2016/01/28 18:05 (external edit)