Cypress CY14B104N Manual De Usuario
CY14B104L, CY14B104N
Document #: 001-07102 Rev. *L
Page 5 of 25
Hardware RECALL (Power Up)
During power up or after any low power condition
(V
(V
CC
< V
SWITCH
), an internal RECALL request is latched. When
V
CC
again exceeds the sense voltage of V
SWITCH
, a RECALL
cycle is automatically initiated and takes t
HRECALL
to complete.
During this time, HSB is driven LOW by the HSB driver.
Software STORE
Transfer data from the SRAM to the nonvolatile memory with a
software address sequence. The CY14B104L/CY14B104N
software STORE cycle is initiated by executing sequential CE
controlled read cycles from six specific address locations in
exact order. During the STORE cycle an erase of the previous
nonvolatile data is performed, followed by a program of the
nonvolatile elements. After a STORE cycle is initiated, further
input and output are disabled until the cycle is completed.
software address sequence. The CY14B104L/CY14B104N
software STORE cycle is initiated by executing sequential CE
controlled read cycles from six specific address locations in
exact order. During the STORE cycle an erase of the previous
nonvolatile data is performed, followed by a program of the
nonvolatile elements. After a STORE cycle is initiated, further
input and output are disabled until the cycle is completed.
Because a sequence of READs from specific addresses is used
for STORE initiation, it is important that no other read or write
accesses intervene in the sequence. Further, no read or write
operations must be done after the sixth address read for a
duration of soft-sequence processing time (t
for STORE initiation, it is important that no other read or write
accesses intervene in the sequence. Further, no read or write
operations must be done after the sixth address read for a
duration of soft-sequence processing time (t
SS
). If these condi-
tions are not met, the sequence is aborted and no STORE or
RECALL takes place.
RECALL takes place.
To initiate the software STORE cycle, the following addresses
and read sequence must be performed.
and read sequence must be performed.
1. Read Address 0x4E38 Valid READ
2. Read Address 0xB1C7 Valid READ
3. Read Address 0x83E0 Valid READ
4. Read Address 0x7C1F Valid READ
5. Read Address 0x703F Valid READ
6. Read Address 0x8FC0 Initiate STORE Cycle
The software sequence may be clocked with CE controlled reads
or OE controlled reads. After the sixth address in the sequence
is entered, the STORE cycle commences and the chip is
disabled. HSB will be driven LOW.
or OE controlled reads. After the sixth address in the sequence
is entered, the STORE cycle commences and the chip is
disabled. HSB will be driven LOW.
It is important to use read
cycles and not write cycles in the sequence, although it is not
necessary that OE be LOW for a valid sequence. After the
t
necessary that OE be LOW for a valid sequence. After the
t
STORE
cycle time is fulfilled, the SRAM is activated again for the
read and write operation.
Software RECALL
Transfer the data from the nonvolatile memory to the SRAM with
a software address sequence. A software RECALL cycle is
initiated with a sequence of read operations in a manner similar
to the software STORE initiation. To initiate the RECALL cycle,
the following sequence of CE controlled read operations must be
performed.
a software address sequence. A software RECALL cycle is
initiated with a sequence of read operations in a manner similar
to the software STORE initiation. To initiate the RECALL cycle,
the following sequence of CE controlled read operations must be
performed.
1. Read Address 0x4E38 Valid READ
2. Read Address 0xB1C7 Valid READ
3. Read Address 0x83E0 Valid READ
4. Read Address 0x7C1F Valid READ
5. Read Address 0x703F Valid READ
6. Read Address 0x4C63 Initiate RECALL Cycle
Internally, RECALL is a two step procedure. First, the SRAM data
is cleared; then, the nonvolatile information is transferred into the
SRAM cells. After the t
is cleared; then, the nonvolatile information is transferred into the
SRAM cells. After the t
RECALL
cycle time, the SRAM is again
ready for read and write operations. The RECALL operation
does not alter the data in the nonvolatile elements.
does not alter the data in the nonvolatile elements.
Table 1. Mode Selection
CE
WE
OE, BHE, BLE
A
15
- A
0
Mode
IO
Power
H
X
X
X
Not Selected
Output High Z
Standby
L
H
L
X
Read SRAM
Output Data
Active
L
L
X
X
Write SRAM
Input Data
Active
L
H
L
0x4E38
0xB1C7
0x83E0
0x7C1F
0x703F
0x8B45
0x8B45
Read SRAM
Read SRAM
Read SRAM
Read SRAM
Read SRAM
Read SRAM
Read SRAM
Read SRAM
Read SRAM
AutoStore
Disable
Output Data
Output Data
Output Data
Output Data
Output Data
Output Data
Output Data
Output Data
Output Data
Output Data
Output Data
Active
Notes
7. While there are 19 address lines on the CY14B104L (18 address lines on the CY14B104N), only the 13 address lines (A
14
- A
2
) are used to control software modes.
The rest of the address lines are don’t care.
8. The six consecutive address locations must be in the order listed. WE must be HIGH during all six cycles to enable a nonvolatile cycle.
9. IO state depends on the state of OE, BHE, and BLE. The IO table shown assumes OE, BHE, and BLE LOW.
9. IO state depends on the state of OE, BHE, and BLE. The IO table shown assumes OE, BHE, and BLE LOW.