writing to the free space in the boot eeprom?

rtowler

First off, thanks to Mike Green for suggesting that I try out the prop. Not only have I chosen it for the project he responded about, but I'm using it for all sorts of projects and having a lot of fun. Tomorrow my first prop project will travel to the bottom of the Bering Sea.

But onto my questions. Pardon if this has been covered before, I have searched the forums for a solution and while I may have uncovered what I need to know, I didn't really understand it all. I am wondering if you can use the "spare" space is the boot eeprom to store data (I think the answer is yes)? If so, how do you determine how much free space is available and the starting address (probably with the prop tool)? What is the best way to read/write data? I am planning on using Mike's Basic I2C Routines.

Bonus points for fast responses This is for that project that will be deployed tomorrow! Nothing like having a project bomb dropped on you.

As always, many thanks for the replies.

-Rick

T Chap

Since you are in a hurry I'll throw out what I think, which stands corrected! If you look in the Propeller tool under Run>Complie Top>Show info you will see the addresses of the EEPROM that the Prop will use( 0 to 7FF0) You can write ABOVE that number and I believe it will stay there forever, the Propeller tool re-writes OVER the 0 - 7FF0 area when programming. You can always add a second EEPROM with a unique address, or use a larger boot EEPROM, not sure of an any advanatge though.

I thought the minimali2cdriver of Mike's included a write and read method, which should be very straighforward if you read the object comments.

Post Edited (originator) : 3/9/2007 7:09:26 PM GMT

parts-man73

If you look at the 5th post down in this thread
http://forums.parallax.com/showthread.php?p=626711

Mike Green states :

Mike Green said...
1) Anything you store in the boot EEPROM is overwritten when you write a new program to EEPROM. The Prop transfers the whole 32K to the EEPROM

This may be a problem, unless a larger EEPROM is used, such as the one on the Protoboard, you can then used the upper 32k for data storage, and the lower 32k the propeller uses for program space.

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Brian Meade

"They who dream by day are cognizant of many things which escape those who dream only by night" - Edgar Poe

rtowler

Thanks originator and pm73. The data will be downloaded regularly and I'll just let the operator know *not* to reprogram w/o downloading his data first!

-Rick