On Fri, Jul 6, 2012 at 12:17 AM, Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> wrote: > On Thu, Jul 05, 2012 at 11:36:27PM +0530, Shubhrajyoti Datta wrote: >> On Thu, Jul 5, 2012 at 6:40 PM, Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> wrote: >> > Measurements on i.MX1 and i.MX53 have shown that the divider values >> > in the datasheets are wrong. >> How were the measurements made? > > With an oscilloscope measuring the period length. This is probably not > very exact, but the current values are way off. We had 350KHz instead > of 380KHz (best possible divider) on an i.MX53. Funny enough some > divider values really match the ones in the datasheet. > > BTW I'm pretty sure the input frequency to the core is calculated > correctly as it's the same clock that also drives the timer. OK thanks for the explanation. > >> >> > the values from first, third and fourth >> > column were all measured to be 8 higher than in the datasheet. It >> > should be safe to assume that the SoCs between i.MX1 and i.MX53 behave >> > the same as the i2c unit is unchanged since the i.MX1. >> >> Also does it vary board to board or is fixed by the ip? >> What I mean is that the external cap etc. > > The clock is derived from an internal SoC clock, I don't think this can > be influenced that much by external components. I did not test different > boards, but two board with different SoCs. OK thanks. > > Let's see what the IC guys tell us. Sure. > > Sascha > > -- > Pengutronix e.K. | | > Industrial Linux Solutions | http://www.pengutronix.de/ | > Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | > Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
