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DToolan
Joined: 14 Aug 2004
Posts: 1384
Location: Dallas / Fort Worth, Texas (USA)
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 Posted: Fri Jun 10, 2005 4:09 am Post subject: |
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Describe "data" storage?
Your program area (flash) can hold all sorts of data... it just has to be written into your program at compile time. Things like strings (days of the week, months of the year), a lookup table for CRC calculations... this is all data.
The ability to write to the program area after programming could produce the possibility of "self-modifying" code (which would be a no-no in most situations). This is why your program, once flashed into the device, is commonly referred to as "firmware"... it's supposed to stay the way you wrote it. Also, the program area (flash) has an endurance of 10,000 write/erase cycles. I'd say this is ok for even the most mistake prone programmer but using that area for changing variable data during run-time could burn a chip out quick.
You do have 4K Bytes of EEPROM in the M128 that you can use for data storage during run-time... are you needing more than that? The endurance of the EEPROM area is 100,000 write/erase cycles. One wouldn't want to store constantly changing values there but things like a weekly sprinkler schedule or lighting schedule (things modifiable but not changed often). Perhaps as a data logger (as long as 4K was big enough)... these uses could be most appropriate for that storage. |
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Brian
Joined: 29 Jul 2004
Posts: 27
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| Posted: Fri Jun 10, 2005 7:45 am Post subject: |
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| The code flash has a lifetime of only 10,000 write/erase cycles. |
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Luciano
Joined: 29 Nov 2004
Posts: 3149
Location: Italy
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Duval JP
Joined: 22 Jun 2004
Posts: 1198
Location: France
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| Posted: Fri Jun 10, 2005 3:43 pm Post subject: |
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hello,
Why do you want write data to the flash program memory ?
Because you need data more than 4K EEPROM I suppose.
But a good idea is it to use AVR DOS see this MCS option, and a flash card
Or to use a I2C memory, very easy, 1000000 reusable, I do that.
bon courage
JP
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