user data protection for power failure
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·· what is the most suitable way to save user data when power failed. I think the software side of this work must be to save user data
·on eeprom land not used by propeller.I need a circuit which know power failed and says to·propeller "save user data power goes out"
also this circuit·turn on·battery power to supply enough time to propeller to save data.is maxim max807 suitable for this project
·· what is the most suitable way to save user data when power failed. I think the software side of this work must be to save user data
·on eeprom land not used by propeller.I need a circuit which know power failed and says to·propeller "save user data power goes out"
also this circuit·turn on·battery power to supply enough time to propeller to save data.is maxim max807 suitable for this project
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If you use a Protoboard, you'd have at least 32K bytes of EEPROM available for saving user data. If you build your own, be sure to use either a 24LC512 EEPROM or a 24C1024 EEPROM (used on the Hydra) rather than the 24LC256 usually used. There are two sets of routines in the Propeller Object Exchange that can be used to access the EEPROM. I suggest the one labelled "Basic I2C Driver". There are examples of its use in the source.
The amount of time you'd need to power the Propeller depends on how much data you'd have to store and on your main program and how long it would take to reach a "check point" where the data to be saved is at a stable point (not in the middle of a computation or partial update). The EEPROMs can write about 128 bytes in a 10ms cycle.
Another alternative would be to use a separate Ramtron FRAM. These work like EEPROMs, but have essentially unlimited write cycles and don't have the 10ms write cycle. Your program could possibly write its data to the FRAM as it is received (or computed) and you wouldn't need a separate backup. During a power outage, your program would simple stop without needing to separately save its last set of data. The FRAM could be attached to the same I/O pins as the boot EEPROM.
to eeprom too.but the problem is on harware side .Propeller needs time to make this works.How can I add super capacitor or chargable power to my sytem.