mfrc531 NXP Semiconductors, mfrc531 Datasheet - Page 75

• Manufacturer Part Number: mfrc531
• Description: Iso/iec 14443 Reader Ic
• Manufacturer: NXP Semiconductors

NXP Semiconductors
MFRC531_34
Product data sheet
PUBLIC
11.1.1 Basic states
11.1.2 StartUp command 3Fh
11.1.3 Idle command 00h
Table 130. StartUp command 3Fh
Remark: This command can only be activated by a Power-On or Hard reset.
The StartUp command runs the reset and initialization phases. It does not need or return,
any data. It cannot be activated by the microprocessor but is automatically started after
one of the following events:
The reset phase comprises an asynchronous reset and configuration of certain register
bits. The initialization phase configures several registers with values stored in the
EEPROM.
When the StartUp command finishes, the Idle command is automatically executed.
Remark:
Table 131. Idle command 00h
The Idle command switches the MFRC531 to its inactive state where it waits for the next
command. It does not need or return, any data.
The device automatically enters the idle state when a command finishes. When this
happens, the MFRC531 sends an interrupt request by setting bit IdleIRq. When triggered
by the microprocessor, the Idle command can be used to stop execution of all other
commands (except the StartUp command) but this does not generate an interrupt request
(IdleIRq).
Remark: Stopping command execution with the Idle command does not clear the FIFO
buffer.
Command
StartUp
Command
Idle
•
•
•
•
•
•
Power-On Reset (POR) caused by power-up on pin DVDD
POR caused by power-up on pin AVDD
Negative edge on pin RSTPD
The microprocessor must not write to the MFRC531 while it is still executing the
StartUp command. To avoid this, the microprocessor polls for the Idle command to
determine when the initialization phase has finished; see
When the StartUp command is active, it is only possible to read from the Page 0
register.
The StartUp command cannot be interrupted by the microprocessor.
Value
3Fh
Value
00h
Rev. 3.4 — 26 January 2010
Action
runs the reset and initialization phase
Action
no action; cancels current command
execution
056634
Section 9.7.4 on page
Arguments
and data
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Arguments
and data
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ISO/IEC 14443 reader IC
MFRC531
© NXP B.V. 2010. All rights reserved.
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