Specifications
CY14C101PA
CY14B101PA
CY14E101PA
Document Number: 001-54392 Rev. *N Page 11 of 44
Write Protection and Block Protection
CY14X101PA provides features for both software and hardware
write protection using WRDI instruction and WP
. Additionally, this
device also provides block protection mechanism through BP0
and BP1 pins of the Status Register.
The write enable and disable status of the device is indicated by
WEN bit of the Status Register. The write instructions (WRSR,
WRITE, WRTC and WRSN) and nvSRAM special instruction
(STORE, RECALL, ASENB, ASDISB) need the write to be
enabled (WEN bit = ‘1’) before they can be issued.
Write Enable (WREN) Instruction
On power-up, the device is always in the write disable state. The
following WRITE, WRSR, WRTC, WRSN, or nvSRAM special
instruction must therefore be preceded by a Write Enable
instruction. If the device is not write enabled (WEN = ‘0’), it
ignores the write instructions and returns to the standby state
when CS
is brought HIGH. A new CS falling edge is required to
re-initiate serial communication. The instruction is issued
following the falling edge of CS
. When this instruction is used,
the WEN bit of Status Register is set to ‘1’. WEN bit defaults to
‘0’ on power-up.
Note After completion of a write instruction (WRSR, WRITE,
WRTC or WRSN) or nvSRAM special instruction (STORE,
RECALL, ASENB, ASDISB), the WEN bit is cleared to ‘0’. This
provides protection from any inadvertent writes. Therefore, the
WREN instruction must be used before a new write instruction
can be issued.
Figure 6. Read Status Register (RDSR) Instruction Timing
Figure 7. Fast Read Status Register (FAST_RDSR) Instruction Timing
Figure 8. Write Status Register (WRSR) Instruction Timing
CS
SCK
SO
01234567
SI
000001 0
0
1
HI-Z
012345 67
Data
LSB
D0D1
D2
D3
D4
D5D6
MSB
D7
Op-Code
CS
SCK
SO
01234567
SI
00001 001
HI-Z
8 9 10 11 12 13 14 15
0
Data
LSB
D0D1
D2
D3
D4
D5D6
MSB
D7
X
X
X
X
X
X
X
X
Dummy Byte
012345 67
Op-Code
CS
SCK
SO
01 23 4567
SI
0000000
1
MSB
LSB
D2
D3D7
HI-Z
012345 67
Opcode
Data in
X
X
X
X
X