Cypress STK14CA8 manual Preventing AutoStore, Low Average Active Power

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STK14CA8

Low Average Active Power

CMOS technology provides the STK14CA8 with the benefit of power supply current that scales with cycle time. Less current is drawn as the memory cycle time becomes longer than 50 ns. Figure 16 shows the relationship between ICC and READ/WRITE cycle time. Worst case current consumption is shown for commercial temperature range, VCC=3.6V, and chip enable at maximum frequency. Only standby current is drawn when the chip is disabled. The overall average current drawn by the STK14CA8 depends on the following items:

1.The duty cycle of chip enable

2.The overall cycle rate for operations

3.The ratio of READs to WRITEs

4.The operating temperature

5.The VCC Level

6.I/O Loading

Figure 16. Current vs Cycle Time

Preventing AutoStore

The AutoStore function can be disabled by initiating an AutoStore Disable sequence. A sequence of READ operations is performed in a manner similar to the software STORE initi- ation. To initiate the AutoStore Disable sequence, the following sequence of E controlled or G controlled READ operations must be performed:

Read Address

0x4E38

Valid READ

Read Address

0xB1C7

Valid READ

Read Address

0x83E0

Valid READ

Read Address

0x7C1F

Valid READ

Read Address

0x703F

Valid READ

Read Address

0x8B45

AutoStore Disable

The AutoStore can be 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 E controlled or G controlled READ operations must be performed:

Read Address

0x4E38

Valid READ

Read Address

0xB1C7

Valid READ

Read Address

0x83E0

Valid READ

Read Address

0x7C1F

Valid READ

Read Address

0x703F

Valid READ

Read Address

0x4B46

AutoStore Enable

If the AutoStore function is disabled or re-enabled, a manual STORE operation (Hardware or Software) must be issued to save the AutoStore state through subsequent power down cycles. The part comes from the factory with AutoStore enabled.

Document Number: 001-51592 Rev. **

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Contents Logic Block Diagram FeaturesDescription Cypress Semiconductor Corporation 198 Champion CourtPin Descriptions PinoutsPin Name Description Symbol Parameter Commercial Industrial Units Min DC CharacteristicsAbsolute Maximum Ratings AC Test Conditions Symbol Parameter Max Units ConditionsCapacitance Sram Read Cycles #1 and #2 Sram Write Cycles #1 and #2 Symbols Parameter AutoStore/POWER UP RecallUnits Standard Alternate Min Max Software Controlled STORE/RECALL Cycle Hardware Store Cycle Soft Sequence CommandsUnits Standard Alternate Min Units Standard Min Max16-A Mode Power Mode SelectionNvSRAM Operation Hardware Recall Power UpNvSRAM AutoStore OperationSoftware Recall Software StoreData Protection Noise ConsiderationsPreventing AutoStore Low Average Active PowerOrdering Codes Ordering InformationPin 300 mil Ssop Pin 300 mil SoicWorldwide Sales and Design Support Products PSoC Solutions Sales, Solutions, and Legal InformationNew data sheet Document History