MLX90132 Datasheet, PDF (23/44 Pages) Melexis Microelectronic Systems – 13.56MHz RFID / NFC Transceiver

MLX90132
13.56MHz RFID / NFC Transceiver
6.7 Listen command (0x05)
This command is used with the MLX90132 in Tag emulation state to listen for the command from the reader.
Before sending this command the application has to select a protocol using “Protocol Select” command with
the related options.
Listen0x05
Direction
MCU – device
Device - MCU
Device - MCU
Device - MCU
Device -MCU
Device - MCU
Data
05
00
00
00
82
00
83
00
85
00
8F
00
Comments
Command code
Length of data
Result code
Length of data
Error code
Length of data
Error code
Length of data
Error code
Length of data
Error code
Length of data
Example
0500 – Listen for a request from reader
0000- No error. Confirmation that device now is in listening mode
8200 - Invalid command length
8300 - Invalid protocol or protocol is not supported.
8500 - Canceled by user using “Echo” command
8F00 - No HF field detected, command cannot be executed
Table 18: “Listen” command description
When the “listen” command is executed and the option “Waits for field” is activated, the MLX90132 waits for
the HF field activation and corresponding request coming from an RFID reader.
If the option “Return an error if no field” is activated, the MLX90132 directly returns an error if no HF field is
detected.
If the HF field is interrupted by the reader while the MLX90132 is waiting for the request, it will leave the listen
command and return the error code 0x8F00.To wait for new request, the application must issue a new “listen”
command.
The user can cancel the “listen” mode by issuing an “echo” command 0x55. When cancelled, the MLX90132
replies with a code 0x55 (as a sync reply) plus “Cancelled by user” message corresponding to 0x85, 0x00. To
cancel the “listen” mode, the following procedure should be followed:
 Send the ECHO command 0x55 to cancel the “listen” mode
 Set the pin SPI_NSS to low, to read back the buffer content
 Read the sync reply 0x55
 By keeping SPI_NSS low, read the rest of the buffer (could be cancelled by user 0x8500 message or
correct data information 0x80<LEN><DATA>)
 Set the pin SPI_NSS high to continue the operation
3901090132
Rev. 009
Page 23 of 44
Jan-2014