external eeprom

[ruijc]

Hi guys,

For pics without I2C function like the 12F675 is it possible to read and write data into an external eeprom ?

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[Acetronics2]

Mhhhhhh,

12F675 has a 14 bits core ... ( I Think ) ...

and limitations are for 12 BITS cores ...

from the " README" PbP 2.50a file :

<<

12C508(A), 12C509(A), 12CE518, 12CE519, 12F508, 12F509, 12F510, 12F519,
12F609, 12F615, 12HV609, 12HV615: Limited
support.

12C671, 12C672, 12CE673, 12CE674, 12F629, 12F635, 12F675, 12F683:
Supported.

>>
Alain

[ruijc]

Thanks Alain,

i guess that this maybe a stupid question, but here it goes anyway...

If the 12F675 does not support I2C ( meaning i cannot use the I2Cread and I2Cwrite commands in pbp ) how can i comunicate with the eeprom ?

And the fisical connections are the same ?

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[Darrel Taylor]

Like Alain was saying ...

You CAN use I2CWRITE/READ statements with a 12F675.
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[ruijc]

Thanks Alain and Darrel Taylor,



my previous question is due to the fact that in the 12F675 datasheet it doesnt says that it's compatible like other pics do.

Maybe pbp gets arround that !?

This means i can use the same pbp expressions and the hardware connections the same also, right ?

Thanks

[Darrel Taylor]

The I2CWRITE/READ statements don't use any Hardware I2C modules.
So you can use any pins you want.

The only limitation is on devices with 12-bit cores.
Just because there is a 12 in the part number (12F675), Does Not mean it's a 12-bit core.
<br>

[tenaja]

Thanks Alain and Darrel Taylor,



my previous question is due to the fact that in the 12F675 datasheet it doesnt says that it's compatible like other pics do.

Maybe pbp gets arround that !?

This means i can use the same pbp expressions and the hardware connections the same also, right ?

Thanks

You are confusing hardware features with compiler capability.

Some PIC's have an MSSP or SSP built in to them. The MSSP allows them to be a master i2c through hardware. Doing it through hardware allows the PIC to "multitask" by giving you processor time while the hardware does the work. The SSP only allows slave i2c, which I learned the hard way, and it's basically useless for communicating with eeprom.

The compiler has a command that performs i2c tasks in software. By doing it in software, that gives you the flexibility to do functions with PIC's that don't have the hardware to do it. However, the trade-off is that during the sending time, it consumes 100% of the processing time. (This is what I ended up doing with my PIC that had the SSP.)

[ruijc]

Hi tenaja,

That's exactly what i was looking for

now i fully undestand

Thanks all and happy new year !!!!

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