Is there a way to store and update a single setting on a panda without a microsd or battery?

NETMF & Gadgeteer
1

Hi,

If you have an application that has a single setting (an integer value) that could
be updated by the users and should keep its value even if the device lost power.

Is there a way to do this without a micro sd card or a battery?

2

http://www.ghielectronics.com/downloads/NETMF/Library%20Documentation/html/ccb0e435-a5e2-d315-9be4-b8de5a6fcc85.htm

3

Thnx exactly what I needed.

For other devices,
I was reading about “extended weak references earlier”, and as a side question.
When they say they can survive power cycles, does this mean it survives disconnecting a device from power completely?

4

By the way,

Writing to the flash, it can be done a few thousand times at least right?

(In any case this setting will only be updated like once a year anyway)

5

I think the limit is usually around 10,000 times.

Curious though… If the flash is “worn out” from too many writes does that disable the device fully or only the ability to write to the flash in the future?

6

I suspect most flash “failures” don’t result in a hard-fault like a failed hard drive sector does, but simply a read that returns data that is potentially wrong. Dangerous Prototypes have a flash destroyer project, [url]http://dangerousprototypes.com/category/flash-destroyer/[/url], that attempted to show this - they used a process to write a known value and read it back and when they got an incorrect value returned they knew the failure had occurred.

7

I understand but my concern was more about whether the device uses the flash for anything internally and shares the space with the user or is it totally there for the user to destroy? In other words, if you do destroy it are you potentially corrupting any of the firmware functionality also?

8

One thing I’m going to do is store the number of writes to the flash, in the flash.
This should at least give us an indication of the flash health when we request the status of the device.

I also like the idea of storing a known value and checking that when loading the flash. thnx

9

Generally Flash is divided into sectors. A full sector has to be erased and rewritten. That wears out only that sector. So if you do destroy that part of the flash then the rest, that the MF runs from, will still be fine.

I don’t know if a full MF firmware reflash tries to erase this space. That might mean that a firmware upgrade might fail.

10

Hello Gus,

I want to see your link, but doesn´t work.

Is possible to send a new link??

thanks in advance.

11

Go to the support link above and find the netmf 4.1 reference (assuming you’re still looking for panda/usbizi)

12

@ rlcobos - I am not sure what the link was pointing to, but given the context it seems like it might have been to documentation for ExtendedWeakReference

There are also samples

13

http://www.ghielectronics.com/downloads/NETMF/Library%20Documentation%20v4.1/html/ccb0e435-a5e2-d315-9be4-b8de5a6fcc85.htm

InternalFlashStorage class

1 Like
14

@ rlcobos - here’s an example of code you which might be helpful too http://www.tinyclr.com/forum/topic?id=10430