20x2 non volatile memory

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smeagol

Member
Hi all,

after searching through the forum I'm a bit unsure of the non volatile memory available on the 20x2, various posts seem to contradict each other (from contributors who appear to have a good knowledge of the picaxe).

So could someone confirm if Table memory is non volatile on the 20x2.

I want to use the eeprom to store variables that will survive power down.

I also have a lot of static data so if Table is non volatile I can use this and save program space. (External i2c eeprom is not possible at the moment)

Cheers
Gavin
 
W

westaust55

Moderator
Keep in mind that TABLE memory is a part of the program memory space.
For X1/X2 parts there are a maximum 256 bytes and for M2 parts there is 512 bytes available.
TABLE memory can be more efficient than using lots of values embedded in program statement is used well.
Keep in mind that because it is using a part of program space, the available program space will be reduced accordingly for each byte of TABLE memory used.
 
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westaust55

Moderator
Yes,
EEPROM is a separate memory area (except on a few PICAXE chips).
By virtue of the type of memory and the method of access in the PIC structure, EEPROM is a little slower.
 
N

nick12ab

Senior Member
pepijndevos said:
So I assume the EEPROM/DATA command is similar(but slower?), and does not affect program memory?
Click to expand...
On some parts the EEPROM is separate from the program memory and on others it too is shared, in which case the only difference between it and TABLE is that EEPROM data can be modified by the PICAXE program but TABLE cannot.

See here for a list of which PICAXEs use shared memory and which use dedicated memory.
 
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