Rainbow Electronics MAX66020 - Manual (Page 20)

MAX66020
ISO/IEC 14443 Type B-Compliant
1Kb Memory Fob
20 ______________________________________________________________________________________
shows where this information is located in the protocol
info field and what the values are.
The bit-rate capability of the MAX66020 ranges from
105.9kbps to 847.5kbps in both directions (request and
response); request and response bit rate need not be
the same. The maximum frame size (upper nibble of the
2nd byte) of any request/response specifies 24 bytes.
The largest frame that occurs with the MAX66020 is 19
bytes (Get System Information response). The protocol
type (lower nibble of the 2nd byte) specifies that the
MAX66020 supports the ISO/IEC 14443-4 block trans-
mission protocol. The FWI code 0110b specifies a
frame waiting time of 19.3ms. Note that a slave may
respond long before the maximum frame waiting time is
expired. The ADC code 00b specifies that the
MAX66020 uses proprietary coding for the application
data field. The FO code 01b implies that the MAX66020
supports CID, but does not support the NAD field in the
ISO/IEC 14443-4 block transmission protocol.
HLTB Command
The HLTB command is the only network function com-
mand to silence a slave by parking it in the HALT state.
If, based on the ATQB response, the master does not
want to further communicate with the slave, the master
issues the HLTB command. Figures 23 and 24 show
the format of the HLTB request frame and the corre-
sponding response frame. The data to be used in the
PUPI field must match the PUPI information that the
slave has transmitted in the ATQB response. While in
the HALT state, the slave only responds to the WUPB
request.
ATTRIB Command
The ATTRIB command is the only way to select a slave
and make it process commands that are transmitted
according to the ISO/IEC 14443 block transmission pro-
tocol. If, based on the ATQB response, the master
wants to communicate with the slave, the master must
put the slave into the ACTIVE state using the slave
selection command ATTRIB. The normal way for the
master to move a slave out of the ACTIVE state is by
sending a DESELECT command, which uses an
S-block to convey a network function command.
Figure 25 shows the format of the ATTRIB request
frame. The data to be used in the PUPI field must
match the PUPI information that the slave has transmit-
ted in the ATQB response. Param 1 tells the slave how
much time the master needs to switch from transmit to
receive (TR0), how much time the master needs to syn-
chronize to the slave’s subcarrier (TR1), and whether
the master is capable of receiving response frames
without SOF and/or EOF.
The MAX66020 ignores the data of Param 1. To ease
requirements for ISO/IEC 14443 Type B readers, the
MAX66020 has TR0 and TR1 fixed at 128/fs (151µs; fs
is the subcarrier frequency of 847.5kHz) and always
begins and ends its responses with SOF and EOF,
respectively.
1ST BYTE 2ND BYTE
3RD BYTE,
UPPER NIBBLE
3RD BYTE,
BIT 4, BIT 3
3RD BYTE,
BIT 2, BIT 1
BIT RATE CABILITY MAXIMUM FRAME SIZE, PROTOCOL TYPE FWI ADC FO
77h 11h 0110b 00b 01b
Figure 22. Protocol Info Field Details
COMMAND SOF CRC EOF
1Dh (2 BYTES)
PUPI
(4 BYTES)
PARAM 1
(1 BYTE)
PARAM 2
(1 BYTE)
PARAM 3
01h
PARAM 4
(1 BYTE)
HLINF
( ≥ 0 BYTES)
Figure 25. ATTRIB Request Frame
COMMAND SOF CRC EOF
50h (2 BYTES)
PUPI
(4 BYTES)
Figure 23. HLTB Request Frame
INDICATOR SOF CRC EOF
00h (2 BYTES)
Figure 24. HLTB Response Frame