pca24s08a NXP Semiconductors, pca24s08a Datasheet - Page 12

• Manufacturer Part Number: pca24s08a
• Description: 1024 ? 8-bit Cmos Eeprom With Access Protection
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCA24S08A_1
Product data sheet
Bit 0 in the same byte emulates a TAMPER bit and is always equal to 0. TAMPER is a
read-only bit. Attempt to write a ‘1’ to this bit will be ignored.
Byte 11 through byte 14 are currently reserved and should not be used by the system.
Byte 14 may not be written by the device at any time.
Byte 11 to byte 13 are read/write bytes that are stored in the EEPROM.
Byte 14 is a read-only byte and the returned value during a read operation is FFh. A write
on it is acknowledged, but the write will be ignored.
Byte 15 contains device revision information stored in the EEPROM. It is set at the wafer
production facility and cannot be changed in the field, so any write to this byte will be
ignored but acknowledged. The value of this byte is 10h.
The memory map for the Access Protection Page is shown in
In this table, an ‘X’ means that the value is a ‘Don’t care’ upon writing, and that it is
undefined upon reading. The PB fields are all 2 bits wide, and the Device Revision field is
8 bits wide. All other fields are 1 bit wide.
With the exception of the 9 Sticky Bits (SB), the two coil detect bits (DE and DC), the
tamper bit (TAMPER), and bytes 14 and 15, all bits within the Access Protection Page are
stored in EEPROM memory. Their state does not change if power is removed or when the
PROT pin is held LOW.
The following page of memory (accessed with A4 = 1) emulate the ID field that would be
transmitted by the device from the RFID port. Bytes within it are accessed with the
address byte at B8h or B9h (write/read). Reading and writing to this page is permitted
when PBAP is 11.
Fig 11. Device access examples
1
a. Write operations
b. Read operations
0
1
1
1
1
0
Rev. 01 — 19 January 2010
0
0
1
0
1
1
0
1024 × 8-bit CMOS EEPROM with access protection
0
0
0
0
1
P0 A3 A2 A1 A0
P0 is used to distinguish between
the APP and RFID pages:
D7
0 = APP pages
1 = RFID pages
D6 D5 D4 D3 D2 D1 D0
D7
Table 5 “APP memory
PCA24S08A
D6 D5 D4 D3 D2 D1 D0
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© NXP B.V. 2010. All rights reserved.
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map”.