6

AT88RF020

2010C–RFID–2/06

Figure 2. AT88RF020 Anticollision and State Transition Flow Chart

Power On

Reset

Wait for REQB

or WUPB

AFI Match ?

Is N = 1?

Select Random

Number "R" in

Range 1 to "N"

Is R = 1?

Wait for

Slot Marker = "R"

Send ATQB

Response

Wait for ATTRIB or HLTB

with PUPI match

Receive CID

Assignment

Send Answer

to HLTB

ACTIVE

State

HALT

State

Wait for WUPB

with AFI match

NO

YES

NO

YES

YES

NO

REQB or WUPB

REQB or WUPB

ATTRIB

HLTB

DESELECT

Matched

Slot

Marker

Send Answer

to ATTRIB

The AT88RF020 processes the following commands when in the

ACTIVE state and only when the CID embedded in the command

matches the CID assigned to the IC :

READ

WRITE

LOCK

CHECK PASSWORD

COUNT

DESELECT

All other commands are ignored when the IC is in the ACTIVE state.