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| ADVANCE | CY14E102L, CY14E102N | |
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Hardware RECALL (Power Up)
During power up or after any low power condition (VCC< VSWITCH), an internal RECALL request is latched. When VCC again exceeds the sense voltage of VSWITCH, a RECALL cycle is automatically initiated and takes tHRECALL to complete.
Software STORE
Transfer data from the SRAM to the nonvolatile memory with a software address sequence. The CY14E102L/CY14E102N software STORE cycle is initiated by executing sequential
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. If there are intervening READ or WRITE accesses, the sequence is aborted and no STORE or RECALL takes place.
To initiate the software STORE cycle, the following 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
Table 1. Mode Selection
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. 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 tSTORE 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:
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 and then, the nonvolatile information is transferred into the SRAM cells. After the tRECALL cycle time, the SRAM is again ready for READ and WRITE operations. The RECALL operation does not alter the data in the nonvolatile elements.
| CE |
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| WE |
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| OE |
| A15 - A0 | Mode | IO | Power |
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| X |
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| X |
| X | Not Selected | Output High Z | Standby |
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| L |
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| H |
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| L |
| X | Read SRAM | Output Data | Active |
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| L |
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| L |
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| X |
| X | Write SRAM | Input Data | Active |
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| L |
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| H |
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| L |
| 0x4E38 | Read SRAM | Output Data | Active[5,6,7] |
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| 0xB1C7 | Read SRAM | Output Data |
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| 0x83E0 | Read SRAM | Output Data |
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| 0x7C1F | Read SRAM | Output Data |
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| 0x703F | Read SRAM | Output Data |
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| 0x8B45 | AutoStore | Output Data |
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| Disable |
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| L |
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| H |
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| L |
| 0x4E38 | Read SRAM | Output Data | Active[5,6,7] |
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| 0xB1C7 | Read SRAM | Output Data |
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| 0x83E0 | Read SRAM | Output Data |
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| 0x7C1F | Read SRAM | Output Data |
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| 0x703F | Read SRAM | Output Data |
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| 0x4B46 | AutoStore Enable | Output Data |
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Notes
5.The six consecutive address locations must be in the order listed. WE must be HIGH during all six cycles to enable a nonvolatile cycle.
6.While there are 18/17 address lines on the CY14E102L/CY14E102N, only the lower 16 lines are used to control software modes.
7.IO state depends on the state of OE, BHE, and BLE. The IO table shown assumes OE, BHE, and BLE LOW.
Document Number: | Page 5 of 21 |
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