Rainbow Electronics MAX66140 - Manual (Page 14)

MAX66140
Request Data for the Inventory Command
Response Data for the Inventory Command (No Error)
This response is generated only if a slave qualifies to respond. In case of an error in the request, slaves do not
respond.
When receiving the Inventory command, the slave devices in the RF field enter the collision management sequence.
If a slave meets the conditions to respond, it sends out a response data packet. If multiple slaves qualify, e.g., AFI,
mask, and slot counter are not used, the response frames collide and are not readable. To receive readable
response frames with the UID and DSFID, the master must eliminate the collision.
Not knowing the slave population, the master could begin with a mask length of 0 and activate the slot counter. By
using this method and going through all 16 slots, the master has a chance to receive clean responses (i.e., the slave
is identified) as well as colliding responses. To prevent a slave that has been identified from further participating in
the collision management sequence, the master transitions it to the quiet state. Next, the master issues another
Inventory command where the slot number that previously generated a collision is now used as a 4-bit mask, and
runs again through all 16 slots. If a collision is found, another inventory command is issued, this time with a mask that
is extended at the higher bits by the slot counter value that produced the collision. This process is repeated until all
slaves are identified. For a full description of the Inventory command processing by the slave device and the timing
specifications, refer to ISO 15693 Part 3, Sections 8 to 9.
Stay Quiet
This command addresses an individual slave and transitions it to the quiet state. The request must be sent in the
addressed mode (Select_flag bit = 0, Address_flag bit = 1). The slave transitioning to the quiet state does not send a
response.
Request Data for the Stay Quiet Command
Select
This command addresses an individual slave and transitions it to the selected state. The request must be sent in the
addressed mode (Select_flag bit = 0, Address_flag bit = 1). The slave transitioning to the selected state sends a
response. If there was a slave with a different UID in the selected state, then that slave transitions to the ready state
without sending a response.
ISO 15693-Compliant Secure Memory
16 ______________________________________________________________________________________
ABRIDGED DATA SHEET
REQUEST FLAGS COMMAND
AFI
(NOTE 1)
MASK LENGTH
MASK PATTERN
(NOTE 2)
(1 Byte) 01h (1 Byte) (1 Byte) (Up to 8 Bytes)
Note 1: The AFI byte is transmitted only if the AFI_flag bit is set to 1. The AFI byte, if transmitted, narrows the range of slaves that
qualify for responding to the request.
Note 2: The mask pattern is transmitted only if the selection mask length is not 0. If the mask length is not an integer multiple of 8,
the MSB of the mask pattern must be padded with 0 bits. The LSB of the mask pattern is transmitted first.
RESPONSE FLAGS DSFID UID
00h (1 Byte) (8 Bytes)
REQUEST FLAGS COMMAND UID
(1 Byte) 02h (8 Bytes)