2

AT88RF020

2010C–RFID–2/06

All bits are sent to or read from the chip least significant bit first. Bit fields listed in this

document are listed with the LSB on the left and the MSB on the right. Multibyte informa-

tion is sent to the chip least significant byte first.

The first byte sent to the chip is stored in memory at the lowest address, and the internal

address is incremented for subsequent bytes. Information is read from the memory and

transmitted by the chip in exactly the same order in which it was written: the first bit writ-

ten is the first bit read.

This specification follows the nomenclature found within the ISO/IEC 14443 document.

Proximity Coupling Device (PCD) is the reader/writer, and Proximity Integrated Circuit

Card (PICC) is the tag/card. ETU refers to Elementary Time Unit, which is the time

required to transmit or receive one bit. One ETU is equal to 128 carrier cycles (9.439

µs). RFU refers to any feature, item, bit field or bit that is held as Reserved for Future

Use. When the reader/writer sends data to this device, RFU bits should always be “0”.

When this device sends data to the reader/writer, RFU bits are undefined.

Memory Map

The memory array within this device is organized as shown in Table 1.

Bytes marked “–” in Table 1 are user-defined and will be set to 0x00 upon shipment from

Atmel. The chip accesses these bytes using specific commands described later in this

document.

A total of 1904 bits (238 bytes) are available for user-defined purposes, including the

Reserved and Signature fields but excluding the PUPI, LockBits, Counter and Password

fields in the above memory map.

The fields named above are defined as follows:

Pseudo Unique PICC Identifier: This PUPI field is a unique serial number permanently

written into the device’s nonvolatile memory at the Atmel factory during wafer probe/test.

It cannot be modified and is guaranteed to be unique for all AT88RF020 devices. Cus-

tomers desiring serial numbers longer than 32 bits are expected to use other locations

within the memory, including the Reserved field within Page 1.

Application Data: This field is transmitted unmodified from the card to the reader/writer

as part of the ATQB command response.

Counter: This field is automatically incremented by the device whenever the COUNT

instruction is executed. It is factory set to the value of zero upon shipment from Atmel.

Table 1. Memory Map

Byte 0

Byte 1

Byte 2

Byte 3

Byte 4

Byte 5

Byte 6

Byte 7

Page 0

Pseudo Unique PICC ID

LockBits

Page 1

Application Data

Reserved

Page 2

Signature

Counter

Page 3

Password

Page 4

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