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leandrohat
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« on: October 15, 2012, 09:08:52 am »
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a variable "int" will be storage in SRAM memory. right?
a "const int" will be storage in SRAM memory or in flash memory?
how can i do for storage an array in a FLASH memory? only with PROGMEM?
my array is char img(5000);
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tuxduino
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« Reply #1 on: October 15, 2012, 09:12:21 am »
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Have you tried searching for PROGMEM on this site ?

http://www.arduino.cc/en/Reference/PROGMEM
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PaulS
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« Reply #2 on: October 15, 2012, 09:15:33 am »
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how can i do for storage an array in a FLASH memory? only with PROGMEM?
Yes. Keep in mind that Flash memory is read-only.

What are you doing with 5000 bytes of image data?
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retrolefty
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« Reply #3 on: October 15, 2012, 09:16:02 am »
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Quote from: leandrohat on October 15, 2012, 09:08:52 am
a variable "int" will be storage in SRAM memory. right?
Correct
a "const int" will be storage in SRAM memory or in flash memory?
SRAM
how can i do for storage an array in a FLASH memory? only with PROGMEM?
Correct, and you will need to use specific commands to read them back in your sketch from flash.
my array is char img(5000);

http://arduino.cc/en/Reference/PROGMEM
Lefty
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Jack Christensen
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« Reply #4 on: October 15, 2012, 09:23:00 am »
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Is "const int" likely to be optimized out of SRAM by the compiler?
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AWOL
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« Reply #5 on: October 15, 2012, 09:25:14 am »
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Is "const int" likely to be optimized out of SRAM by the compiler?
Depends very much how it is used.
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tuxduino
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« Reply #6 on: October 15, 2012, 09:37:22 am »
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Quote from: AWOL on October 15, 2012, 09:25:14 am
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Is "const int" likely to be optimized out of SRAM by the compiler?
Depends very much how it is used.

Hmmm... after all it's just a typed #define. IOW, a literal...
* tuxduino thinks...
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AWOL
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« Reply #7 on: October 15, 2012, 11:45:40 am »
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Hmmm... after all it's just a typed #define. IOW, a literal.
Ever tried taking the address of a #define?
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tuxduino
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« Reply #8 on: October 15, 2012, 02:53:53 pm »
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Quote from: AWOL on October 15, 2012, 11:45:40 am
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Hmmm... after all it's just a typed #define. IOW, a literal.
Ever tried taking the address of a #define?
Well, I know a const is _not_ a typed #define. I was just saying a const can be viewed as a literal.

Taking the address of a const variable is probably one of the things that prevents the compiler from optimizing them out...
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