A C R 3 8 S m a r t C a r d R e a d e r / W r i t e r
Response data format
Header
Status
Data length
BYTE 1
…
…
BYTE N
SW1
SW2
LEN
01
H
BYTE x
Data read from memory card
SW1, SW2
= 90
H
00
H
if no error
WRITE_ONE_BYTE_MEMORY_CARD
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 at 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 write mode can therefore only be used
for updating the counter value in the card.
c) Write with backup enabled (SLE4436 and SLE5536 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 and SLE5536 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 write 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.
ACR38 Reference Manual
Version 2.2 January 2008
Page
39
of 44