Uno - Power Off Memory

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campbellk
 
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Joined: Sat Feb 21, 2015 4:25 am

Uno - Power Off Memory

Post by campbellk »

Adafruit.....first question post. Not sure I'm in the correct forum. Please advise if not.

Have a control project that is using the Uno. Powering application from 4.5V battery pack. Need to conserve energy to eliminate need to replace batteries often. Can't use plug-in power supply. Need to power up Uno and perform required control actions when user presses button. External micro relay will seal in +5V power to Uno. At completion of control actions, Uno will open up power seal-in relay and power off Uno. Questions....

1) I record that status of an output the last time Uno was powered off. Currently, I'm planning on using a latching relay, set prior to power off. I'm looking for a more elegant and/or simpler way to accomplish this. Only need a binary 1 or 0 for record of status. Is there a way to write the 1 or 0 to on-board non-volitile memory that can be read on power up. There may be an chip that could perform this function......just don't know what device will hold state on loss of power, other than latching relay. Thoughts??

2) I haven't tested this yet, but what can I expect the time period will be, in seconds, from application of +5V power to the Uno to restoration of control code execution (ie.. ability to read/write IO and execute code)?

3) I need to add some auxilary components that will be controlled by the Uno. So I will need a PCB manufactured with header connections to the Uno. This obviously be after prototyping/testing is complete. New to the process......do I need to work with a PCB manufacturer to accomplish or can Adafruit provide/facilitate this service?

Thanks for you input.

Kent

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adafruit_support_bill
 
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Re: Uno - Power Off Memory

Post by adafruit_support_bill »

1) You can write your status data to EEPROM.
2) With the standard bootloader, there will be a few seconds lag. You can replace the standard bootloader to reduce or eliminate that lag if needed.
3) We do not offer custom engineering services. However, we do have a contracts category in our Jobs board.
https://www.adafruit.com/jobs

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campbellk
 
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Re: Uno - Power Off Memory

Post by campbellk »

Bill....thank you very much. This helps.

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