To read the identification information, the CS pin must first be asserted and the opcode of 9FH
must be clocked into the device. After the opcode has been clocked in, the device will begin out-
putting the identification data on the SO pin during the subsequent clock cycles. The first byte
that will be output will be the Manufacturer ID followed by two bytes of Device ID information.
The fourth byte output will be the Extended Device Information String Length, which will be 00H
indicating that no Extended Device Information follows. As indicated in the JEDEC standard,
reading the Extended Device Information String Length and any subsequent data is optional.
Deasserting the CS pin will terminate the Manufacturer and Device ID Read operation and put
the SO pin into a high-impedance state. The CS pin can be deasserted at any time and does not
require that a full byte of data be read.
14.1 Manufacturer and Device ID Information
14.1.1
Byte 1 – Manufacturer ID
JEDEC Assigned Code
Hex
Value
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
1FH
0
0
0
1
1
1
1
1
Manufacturer ID
1FH = Atmel
14.1.2
Byte 2 – Device ID (Part 1)
Family Code
Density Code
Hex
Family Code
Density Code
001 = DataFlash
00100 = 4-Mbit
Value
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
24H
0
0
1
0
0
1
0
0
14.1.3
Byte 3 – Device ID (Part 2)
MLC Code
Product Version Code
Hex
MLC Code
000 = 1-bit/Cell Technology
00000 = Initial Version
Value
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
00H
0
0
0
0
0
0
0
0
Product Version
14.1.4
Byte 4 – Extended Device Information String Length
Byte Count
Hex
Value
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
00H
0
0
0
0
0
0
0
0
Byte Count
00H = 0 Bytes of Information
CS
9FH
Opcode
SI
1FH
24H
00H
00H
Data
Data
SO
Manufacturer ID
Device ID
Byte 1
Device ID
Byte 2
Extended
Device
Extended
Device
Extended
Device
Byte n
Information
String Length
Information
Byte x
Information
Byte x + 1
Each transition
represents 8 bits
This information would only be output
if the Extended Device Information String Length
value was something other than 00H.
Note:
Based on JEDEC publication 106 (JEP106), Manufacturer ID data can be comprised of any number of bytes. Some manufacturers may have
Manufacturer ID codes that are two, three or even four bytes long with the first byte(s) in the sequence being 7FH. A system should detect code
7FH as a “Continuation Code” and continue to read Manufacturer ID bytes. The first non-7FH byte would signify the last byte of Manufacturer ID
data. For Atmel (and some other manufacturers), the Manufacturer ID data is comprised of only one byte.
26
AT45DB041D
3595L–DFLASH–4/08
ATMEL [ ATMEL ]
