On 20/02/2011 18:34, Carl Denk wrote:
> I have an 18F4320 with 8mz crystal and a DS1307 RTC, and trying to set
> up the Library I2C (Not software) to drive the DS1307. In the 18F4320
> Data sheet, Table 17-3 (I2C Clock with W/BRG) There are FOSC values of
> 40, 16, 10, and 4 mhz., but not 8 mhz. that I have. What value should I
> use for SSPADD? I am following the example here:
> http://www.microchip.com/forums/tm.aspx?m=3D515040&high=3DI2C+DS1307.
>
> Any other thoughts appreciated too. :)

Looking at the tables and comparing the values, it looks like the=20
formula is Fcy / (BRG + 1)
So for 100 kHz @ Fosc 8MHz it would be 2MHz / (19 + 1) =3D 100 kHz. (19 is=
=20
in decimal =3D 0x13 for hex)
(Fcy is instruction cycles =3D Fosc / 4)

--=20
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