FM25V02 - 256Kb SPI FRAM
Sleep Mode
Enter Sleep
Mode
A
low power mode called Sleep Mode is
implemented on both FM25V02 and FM25VN02
devices. The device will enter this low power state
when the SLEEP op-code B9h is clocked-in and a
rising edge of /S is applied. Once in sleep mode, the
C and D pins are ignored and Q will be high-Z, but
the device continues to monitor the /S pin. On the
next falling edge of /S, the device will return to
normal operation within tREC (400 µs max.). The Q
pin remains in a hi-Z state during the wakeup period.
The device will not necessarily respond to an opcode
within the wakeup period. To start the wakeup
procedure, the controller may send a “dummy” read,
for example, and wait the remaining tREC time.
S
C
D
Q
Figure 12. Sleep Mode Entry
Device ID
The FM25V02 and FM25VN02 devices can be interrogated for its manufacturer, product identification, and die
revision. The RDID op-code 9Fh allows the user to read the manufacturer ID and product ID, both of which are
read-only bytes. The JEDEC-assigned manufacturer ID places the Ramtron identifier in bank 7, therefore there are
six bytes of the continuation code 7Fh followed by the single byte C2h. There are two bytes of product ID, which
includes a Family code, a Density code, a Sub code, and Product Revision code.
Table 6. Manufacturer and Product ID
Bit
7
0
0
0
0
0
0
1
6
1
1
1
1
1
1
1
5
1
1
1
1
1
1
0
4
1
1
1
1
1
1
0
3
1
1
1
1
1
1
0
2
1
1
1
1
1
1
0
1
1
1
1
1
1
1
1
0
1
1
1
1
1
1
0
Hex
7F
7F
7F
7F
7F
7F
C2
Manufacturer ID
Continuation code
Continuation code
Continuation code
Continuation code
Continuation code
Continuation code
JEDEC assigned Ramtron C2h in bank 7
Family
0
Density
Hex
22h
Device ID (1st Byte)
Device ID (2nd Byte)
0
1
0
0
Rev.
0
0
0
1
0
0
Density: 01h=128K, 02h=256K, 03h=512K, 04=1M
00h=FM25V02, 01h=FM25VN02
Sub
Rsvd
0
0
0
0
0
00h
S
C
. . . . . . .
D
Q
9Fh
C2h
22h
7Fh
1
…
7Fh
6
Six bytes of continuation code 7Fh
Figure 13. Read Device ID
Rev. 2.0
May 2010
Page 9 of 17
RAMTRON [ RAMTRON INTERNATIONAL CORPORATION ]
