Preventing autostore – Cypress CY14B104M User Manual
Page 5
PRELIMINARY
CY14B104K, CY14B104M
Document #: 001-07103 Rev. *K
Page 5 of 31
Preventing AutoStore
The AutoStore function is disabled by initiating an AutoStore
disable sequence. A sequence of read operations is performed
in a manner similar to the Software STORE initiation. To initiate
the AutoStore disable sequence, the following sequence of CE
or OE 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 0x8B45 AutoStore Disable
AutoStore is re-enabled by initiating an AutoStore enable
sequence. A sequence of read operations is performed in a
manner similar to the software RECALL initiation. To initiate the
AutoStore enable sequence, the following sequence of CE or OE
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 0x4B46 AutoStore Enable
If the AutoStore function is disabled or re-enabled, a manual
STORE operation (hardware or software) issued to save the
AutoStore state through subsequent power down cycles. The
part comes from the factory with AutoStore enabled.
Table 2. Mode Selection
CE
WE
OE, BHE, BLE
A
15
- A
0
[6]
Mode
I/O
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
Read SRAM
Read SRAM
Read SRAM
Read SRAM
Read SRAM
AutoStore
Disable
Output Data
Output Data
Output Data
Output Data
Output Data
Output Data
Active
L
H
L
0x4E38
0xB1C7
0x83E0
0x7C1F
0x703F
0x4B46
Read SRAM
Read SRAM
Read SRAM
Read SRAM
Read SRAM
AutoStore
Enable
Output Data
Output Data
Output Data
Output Data
Output Data
Output Data
Active
L
H
L
0x4E38
0xB1C7
0x83E0
0x7C1F
0x703F
0x8FC0
Read SRAM
Read SRAM
Read SRAM
Read SRAM
Read SRAM
Nonvolatile
STORE
Output Data
Output Data
Output Data
Output Data
Output Data
Output High Z
Active I
CC2
L
H
L
0x4E38
0xB1C7
0x83E0
0x7C1F
0x703F
0x4C63
Read SRAM
Read SRAM
Read SRAM
Read SRAM
Read SRAM
Nonvolatile
RECALL
Output Data
Output Data
Output Data
Output Data
Output Data
Output High Z
Active
Notes
6. While there are 19 address lines on the CY14B104K (18 address lines on the CY14B104M), only the 13 address lines (A
14
- A
2
) are used to control software modes.
Rest of the address lines are don’t care.
7. The six consecutive address locations must be in the order listed. WE must be HIGH during all six cycles to enable a nonvolatile cycle.