ACR1281U-C1 – Application Programming Interface
Version 1.08
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5.1.7.3.
Write one byte memory card
This command is used to write one byte to the specified address of the inserted card. The byte is
written to the card with LSB first, i.e. the bit card address 0 is regarded as the LSB of byte 0.
Four different
write
modes are available for this card type, which are distinguished by a flag in the
command data field:
a. Write
The byte value specified in the command is written to the specified address. This command can
be used for writing personalization data and counter values to the card.
b. Write with carry
The byte value specified in the command is written to the specified address and the command is
sent to the card to erase the next lower counter stage. This mode can therefore only be used for
updating the counter value in the card.
c. Write with backup enabled (for SLE4436, SLE5536 and SLE6636 only)
The byte value specified in the command is written to the specified address. This command can
be used for writing personalization data and counter values to the card. Backup bit is enabled to
prevent data loss when card tearing occurs.
d. Write with carry and backup enabled (SLE4436, SLE5536 and SLE6636 only)
The byte value specified in the command is written to the specified address and the command is
sent to the card to erase the next lower counter stage. This mode can therefore only be used for
updating the counter value in the card. Backup bit is enabled to prevent data loss when card
tearing occurs.
With all write modes, the byte at the specified card address is not erased prior to the write operation
and hence, memory bits can only be programmed from ‘1’ to ‘0’.
The backup mode available in the SLE4436 and SLE5536 card can be enabled or disabled in the
write operation.
Command
Command
Class
INS
P1
Byte Address MEM_L
Mode
Byte
Read Memory Card
FFh
D0h 00h
02h
Where:
Byte Address
(1 byte)
Memory address location of the memory card
Mode
(1 byte)
Specifies the write mode and backup option
00h = Write.
01h = Write with carry.
02h = Write with backup enabled (for SLE4436, SLE5536 and
SLE6636 only).
03h = Write with carry and with backup enabled (for SLE4436,
SLE5536 and SLE6636 only).
Byte
(1 byte)
Byte value to be written to the card