Setup Guide
Table Of Contents
- Notices
- About Thinkify, LLC
- A Quick RFID Introduction
- Thinkify Reader Protocol Overview
- Command Reference
- Summary
- "A" – RX Amplifier Control
- "BOOTLOADER" – Enter Bootloader
- "C" – Low-Level Chip Control Registers
- "F" – RX Filter Control
- "G" – GPIO Settings
- “I” – Inventory Control
- "K" – Kill, Lock, Access Descriptors
- “M" – MASK / SELECT control
- “NM" – Macro Control
- "P" – PROTOCOL control (Gen2 Air protocol)
- "R" – RF Control
- "RP" and "RM" – Multiplexing (Antenna Control)
- "T" – Initiate INVENTORY
- "X" – eXtra Data Read and Write Descriptor Control
Concepts (Performing an Inventory)
Concepts (Performing an Inventory)
Being an RFID reader trying to read multiple tags using the Gen2 protocol is sort of like being a
new teacher trying to take attendance in a kindergarten class... Sadly, the administration didn't
give you an attendance list on the first day of class so you have to work it out for yourself.
Kindergarten Teacher RFID Reader
You have to get a list of everyone's name. You have to get a list of all of the EPC codes from the tags.
Kids know their own names. Tags have unique IDs in EPC memory they can report.
You can only hear one child at a time. The reader can only process a signal from one tag at a time.
Kids want to all talk at once. Multiple tags can respond at the same time.
What both the teacher and the RFID reader need is an anti-collision protocol – a way to keep
their respective kids/tags from talking at the same time.
Most teachers adopt an adult-talks-first protocol with a persistent state flag for whether a child
has been inventoried. This flag is maintained in the child. Sometimes there's a bi-directional
exchange with an ACK/NAK option. Hey! that's sounds a lot like Gen2.
Teacher Child Gen2 Protocol
“Ok everyone! Quiet down.
It's time to take attendance.”
Reader-talks-first.
“Ok everyone! Hands up!” Under Gen2 this is a Select command that establishes who's going
to participate in the inventory – in this case, everyone. By putting
their hands up, the child has set a flag that indicates he/she hasn't
been inventoried, yet.
“When I point to you, tell me
your first name.”
Granted this is a little contrived, but it's a little like the Query
command in Gen2 that kicks off an inventory sequence.
The teacher randomly picks
the first child, points to her
and says, “You!”
“Inga!” In Gen2, a tag responds to a Query with a random number that is
used in the next command by the reader
“Inga who?” “Svenson!” This is like a Gen2 ACK (acknowledgment). It tells the tag/child that
the reader/teacher heard their response and is now asking them for
their data.
”You!” “Mikey!” At this point, Inga assumes that the teacher got her name, since
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