PCF7936AS/3851/C,1-CT NXP Semiconductors, PCF7936AS/3851/C,1-CT Datasheet - Page 14

• Manufacturer Part Number: PCF7936AS/3851/C,1-CT
• Description: pcf7936as series 32-bit 125 khz read / write security...
• Manufacturer: NXP Semiconductors

NXP Semiconductors
Security Transponder (HITAG2)
7.3.1 Command Description
The general form of a control sequence consists of the
command sequence send to the transponder and an
Equalizer pattern (EQ) and Response received from the
transponder. The general control sequence timing is shown
in Figure 8.
When switching from SEND to RECEIVE and vice versa,
the basestation and control software have to consider the
indicated delays (t
basestation must not transmit any data or commands.
Depending on the command, the Command Sequence
consists of a minimum of 5 bit respectively 10 bit. For data
integrity reasons memory read and write commands have
to be transmitted in normal coding and in inverted coding
before being accepted by the device, which yields a
minimum Command Sequence of 10 bit.
The Equalizer, EQ, consist of a 5 bit pattern (all ones) for
basestation
purposes. The device response consists of a command
acknowledgment and/or the requested data.
2010 May 04
Figure 8. General control sequence timing
Figure 9. Command Idle Time
SEND to
Transponder
RECEIVED from
Transponder
SEND to
Transponder
RECEIVED from
Transponder
settling
WAIT,Tr
Command Sequence
and
and t
software
Response / Parameter
WAIT,Bs
), during which the
synchronization
t
WAIT
,
Tr
EQ
Response
14
Some operations require additional parameter to be send to
and/or to be received from the device, e.g. WRITE_PAGE
or START_AUTH.
For proper operation, command execution by the device
must not be suspended for more than the specified Idle
time (t
command decoding, disabling any communication with the
device. In this case, a LF Field Power-On Reset has to be
applied, in order to reset and initialize the circuitry, see
section 7.7. Consequently, the device resumes WAIT state.
As indicated, the Idle time is specified as the time interval
between the last bit received from the transponder and the
last bit of the Command Sequence send to the
transponder.
command several times for data integrity reasons,
however, in any case the limitations imposed by the Idle
time have to be considered.
The Idle time applies also for the very first command send
to the device after a device LF Field Power-On Reset
condition, see also section 7.7.
t
WAIT
Command Sequence
IDLE
t
IDLE
,
Bs
Parameter
), see Figure 9. Otherwise the device may stop
Some
t
commands
WAIT
,
Tr
EQ
Product Specification
Parameter
allow
PCF7936AS
t
WAIT
CONFIDENTIAL
repeating
,
Tr
the