Add ram and eeprom to 14

[rigidigital]

Is it really really easy to add ram and or eeprom to the 14 ? I just dont want to go to other higher chips.

 

[westaust55]

Not impossible but not easy either.

The 14/14M do not have i2c comms built-in but it could be done by bit-bashing.
Bit bashing will obviously occupy some of the program memory space.

Suggest you search here for more about implementing i2c on the "smaller" PICAXE's

24LCxxx series EEPROMs are readily available for external memory in sizes from 2K to around 32K bytes.
i2c RAM is available generally only available in 256 byte chips.

In another post, I recently indicated that Maxim now have an i2c RTC which incorporates 2K bytes or 4k bytes of RAM Likely a better option than a dedicated RAM chip and you get the time as well.
http://www.picaxeforum.co.uk/showthread.php?t=10252

 

[hippy]

Fairly easy using I2C I would have thought but I've not done it. Any added RAM and Eeprom can only be used as data storage, so you have the overhead of I2C routines plus calls to access that and you're limited to 16 GOSUB commands.

In some cases it may be an apropriate solution but it depends upon what you are wanting to achieve.

 

[kranenborg]

It may actually sometimes be better to simulate SPI instead of I2C (paricularly if only one or maybe two devices are to be connected), as the SPI protocol is simpler. This counts given the limited program memory space in the 08M/14M. Of course you need chip select (the simplicity of the SPI protocol comes at a price, since generally separate chip select is needed for every SPI peripheral, which is why I2C is a much better choice generally), but for a simple 08M datalogging application it may well be worth the effort to write a memory-efficient SPI version. There should be several SPI bit bashing implementations around here

/Jurjen

 

[Dippy]

I think you're going to find it tricky unless hippy or Jurjen write the code for you.
If you flutter your lashes I'm sure they will....

 

[kranenborg]

I'll give it a try soon ...

/Jurjen

 

[Dippy]

Maybe ask if it's a school project first huh?

 

[hippy]

And while the intent is not having to go up to larger more powerful PICAXE's, it may be false economy. Just because it can be done doesn't mean it's the best or ultimately most economical way to do it.