PCF7936AS View Datasheet(PDF) - NXP Semiconductors.
Part Name
Description
MFG CO.
'PCF7936AS' PDF : 33 Pages View PDF
NXP Semiconductors
Security Transponder (HITAG2)
Product Specification
PCF7936AS
WRITE_PAGE
The command WRITE_PAGE writes the data supplied with
this command into the designated page. The page
designated for writing is specified by the command bits pg2
to pg0. For data integrity reasons the 5 bit command and
its complement have to be send, before the device will
accept it, see Figure 15. If accepted, the command
Response consist of the command itself, and the
corresponding complement.
The 10 bit command sequence may be repeated several
times, if desired, to increase the data integrity level. In the
case that one of the 5 bit commands and its complement
do not match, an error condition occurs that causes the
device to terminate the command, to initialize the device
and to enter the WAIT state. No command Response will
be send by the device in this case nor does the designated
page being overwritten.
After termination of tPROG the device checks, if the
EEPROM write operation completed successfully, if not, an
error condition occurs that causes the device to enter the
WAIT state.
In the case the write operation did not complete
successfully, the designated EEPROM page may hold an
undefined content or may suffer from a weak programming.
SEND to
Transponder
WRITE_PAGE
1 0, pg2, pg1, pg0
CM[4:0]
RECEIVED from
Transponder
0 1, pg2, pg1, pg0
CM[4:0]
In order to unambiguously verify, whether programming of
the designated page completed properly, the basestation
has to identify, if the device still resides in AUTHORIZED
state or entered WAIT state. Thus, a READ_PAGE or
READ_PAGE_INV command should be issued
subsequently and monitored, if this command executes
properly.
If the device still resides in AUTHORIZED state, command
execution would complete successfully and after verifying
the data that has been read, proper operation of the
corresponding WRITE_PAGE command can be assumed.
Subsequent commands may be issued after termination of
the final tWAIT,Bs.
Any attempt to write a page that is protected against
overwriting will be detected and cause an error condition,
upon which the device terminates the command during
tWAIT,Tr and enters the WAIT state. No Response will be
send in this case.
If the device is configured for Password mode (ENC = 0)
the command sequence is transmitted in plain, while in
Cipher mode (ENC = 1) the whole command sequence is
transmitted ciphered.
EQ
1 1 1 1 1 1 0, pg2, pg1, pg0 0 1, pg2, pg1, pg0
tWAIT,Tr
CM[4:0]
CM[4:0]
SEND to
Transponder
RECEIVED from
Transponder
Figure 15. WRITE_PAGE timing
Data
bit 31 ..............bit 0
tWAIT,Bs
tIDLE
tPROG
tWAIT,Bs
2010 May 04
19
CONFIDENTIAL
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