WM710xx – Secure F-RAM with Gen-2 RFID
CONTROL/STATUS REGISTER
Accessing the unique features of WM710xx is accomplished through the Control/Status register in F-RAM
non-volatile memory. The register is located at physical address 0x016 or USER memory address 0x002.
The Control/Status word register is organized as shown in Table 3: below. Care should be exercised when
writing the Control/Status register word if it is to remain unlocked.
Table 3: Control/Status Word Register
Bit
15
14
Mnemonic
LOCK
PERMALOCK
Function
Memory locking of this register.
LOCK
0
0
1
PERMALOCK
0
1
0
1
DESCRIPTION
Register unlocked
Register permanently unlocked
Register writeable only from the
SECURED state
Register permanently locked
Initial
Value
0
0
13
12
11
10
9
8
7
6
5
4
RFU
RFU
RFU
RFU
RFU
RFU
BLKWREN
BLKSIZ[2]
BLKSIZ[1]
BLKSIZ[0]
1
Reserved for future use
Reserved for future use
Reserved for future use
Reserved for future use
Reserved for future use
Reserved for future use
0
0
0
0
0
0
1
1
# words
16
32
64
128
1
0
Enables use of the custom command BLOCKWRITE.
USER memory block size.
BLKSIZ[2:0]
# words
BLKSIZ[2:0]
000
1
100
001
2
101
010
4
110
011
8
111
Indicates if the Working Stored Address has wrapped.
3
WRPSTAT
0
2
WRPEN
Logic State
Description
0
Wrapping has not occurred
1
Wrapping has occurred at least once
Enables wrapping of the Working Stored Address when it reaches the
top of logical memory.
Logic State
Description
0
DISABLE memory wrapping
1
ENABLE memory wrapping.
Enable Automatic Locking of all user memory between the start of USER
memory and the Working Stored Address register.
Logic State
Description
0
Auto-lock DISABLED
1
Auto-lock ENABLED
Enable the Working Stored Address word to Auto-Increment when
performing an unaddressed write cycle.
Logic State
0
1
Description
DISABLE auto-increment of stored address register
ENABLE auto-increment of stored address register
0
1
AUTOLOCK
0
0
AUTOINCR
0
Upon power up, WM710xx’s control logic reads the Control/Status word out of memory and configures itself
accordingly. User applications may change the Control Word as needed providing the register has not been
permanently locked. The Control/Status word may be read by the application at any time.
Register Locking:
The LOCK and PERMALOCK control bits are implemented in a similar manner as locking
bits used for Gen2 memory bank locking with the exception that the lock control bits are incorporated into the
Rev. 1.2
Sept. 2010
Page 7 of 17
RAMTRON [ RAMTRON INTERNATIONAL CORPORATION ]
