AT90RF135602 ATMEL, AT90RF135602 Datasheet - Page 14

• Manufacturer Part Number: AT90RF135602
• Description: INTEGRATED 13.56 MHz CONTACTLESS READER WITH EMBEDED SOFTWARE
• Manufacturer: ATMEL

Addressing Modes
AT90RF135602
Command Message
Structure
14
Messages are either single byte or multi-byte.
All messages are terminated by an 8-bit Checksum byte (CSUM) this is calculated as
the 8-bit sum of all the proceeding bytes in the message.
Multi-byte messages are indicated by the most significant bit set to “1” in the first byte of
the message.
The length of the additional information is determined by the message type and nature
of the additional information bytes.
The maximum allowable length of a message including its checksum is 255 bytes.
The host may command Read/Write to the whole of a tag or can restrict the operation to
individual pages and sectors using a common message structure which can be indepen-
dent of tag type.
The v2.7 AT90RF135602 software provides for two modes of addressing tags using
either Logical or Physical addressing depending on the command variant.
For Logical addressing the application can work independent of tag type as long as the
data capacity is not exceeded. The AT90RF135602 software will seamlessly handle the
mapping of logical addresses over to either the Innovision Jewel or the Philips Mifare
Ultralight depending on the type of tag it recognises as being present.
The mapping for logical start address is given in Appendix A.
For Physical addressing the application layer must first know which type of tag is
present and then address the memory bytes using physical addresses from the tag
datasheet.
The user is referred to relevant datasheet documentation.
To wake-up the AT90RF135602 and to start the tag read or write operations the host as
the master must send either a single or a multi-byte Command message.
The single byte message consists of a command byte and checksum byte, as follows:
To AT90RF135602 = <CMD> <CSUM>
(Minimum of 3 bytes +
Single byte message
(1 byte + Checksum)
SPI Message Type
Multi-byte message
Checksum)
1
2
1
2
3
0 – 251 Bytes
Last Byte
st
nd
st
nd
rd
Byte
Byte
Byte
Byte
Byte
Byte
0x00 – 0x7F
Single byte message type
CSUM
0x80 – 0xFF
Multi-byte message type
Information byte
Information byte
Additional information bytes
CSUM
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Description
4407A–SCR–04/05