R
EM4223
Command state transitions
The following tables show the state transitions for each of the commands supported by the EM4223 and should be read in
conjunction with Fig. 19.
Command : Init_Round (Tag will be in ISO mode after this command)
Initial State
Ready
Criteria
Action
New State
AFI in the command = 0 or tags AFI value
matches the value in the command.
Tag chooses a random slot in which it
will send its response. Tag’s Current Slot
Counter is reset to first slot.
None
Round_Active
AFI in the command <> and Tags AFI value <>
AFI value in the command.
Ready
Quiet
None
None
Quiet
Round_Active
AFI in the command = 0 or tags AFI value
matches the value in the command.
Tag chooses a new random slot in which
it will send its response. Tag’s Current
Slot Counter is reset to first slot.
None
Round_Active
AFI in the command <> and Tags AFI value <>
AFI value in the command.
Ready
Round_Standby AFI in the command = 0 or tags AFI value
Tag chooses a new random slot in which
it will send its response. Tag’s Current
Slot Counter is reset to first slot.
Round_Active
matches the value in the command.
AFI in the command <> and Tags AFI value <>
AFI value in the command.
None
Ready
Table 7 – Tag state transitions for Init_Round
Command : New_Round
Initial State
Criteria
Action
New State
Ready
Quiet
Round_Active
None
None
None
None
None
Ready
Quiet
Round_Active
Tag chooses a new random slot in which
it will send its response. Tag’s Current
Slot Counter is reset to first slot.
Round_Standby
None
Tag chooses a new random slot in which
it will send its response. Tag’s Current
Slot Counter is reset to first slot.
Round_Active
Table 8 – Tag state transitions for New_Round
Command : Init_Round_All (Tag will be in ISO mode after this command)
Initial State
Ready
Criteria
Action
New State
None
Tag chooses a random slot in which it
will send its response. Tag’s Current Slot
Counter is reset to first slot.
Round_Active
Quiet
Round_Active
None
None
None
Quiet
Round_Active
Tag chooses a new random slot in which
it will send its response. Tag’s Current
Slot Counter is reset to first slot.
Tag chooses a new random slot in which
it will send its response. Tag’s Current
Slot Counter is reset to first slot.
Round_Standby
None
Round_Active
Table 9 – Tag state transitions for Init_Round_All
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