5

4576D–RFID–12/06

T5554

3.11

Memory

The memory of the T5554 is a 264-bit EEPROM, which is arranged in 8 blocks of 33 bits each.

All 33 bits of a block, including the lock bit, are programmed simultaneously. The programming

voltage is generated on-chip.

Block 0 contains the mode data, which are not normally transmitted (see Figure 3-3).

Blocks 1 to 6 are freely programmable. Block 7 may be used as a password. If password protec-

tion is not required, it may be used for user data.

Bit 0 of every block is the lock bit for that block. Once locked, the block (including the lockbit

itself) cannot be field-reprogrammed.

Data from the memory is transmitted serially, starting with block 1, bit 1, up to block “MAXBLK”,

bit 32. “MAXBLK” is a mode parameter set by the user to a value between 0 and 7 (if maxblk = 0,

only block 0 will be transmitted).

Figure 3-3.

Memory Map

1

032

L

L

L

L

L

L

L

L

Block 7

Block 6

Block 5

Block 4

Block 3

Block 2

Block 1

Block 0

User data or password

32 bits

User data

User data

User data

User data

User data

User data

Configuration data

Not transmitted