Hi Sakari,
On Mon, Oct 17, 2022 at 06:57:48PM +0300, Sakari Ailus wrote:
> Hi Jacopo,
>
> On Mon, Oct 17, 2022 at 05:10:03PM +0200, Jacopo Mondi wrote:
> > > which is also named analog_gain_code_global, but is documented
> > > differently.
> > >
> > > Could you btw read registers 0x0000 to 0x00ff and provide the data ?
> >
> > There is nothing interesting there if not default values. I was hoping
> > that analogue_gain_m0 analogue_gain_c0 and analogue_gain_m1
> > analogue_gain_c1 would provide a way to inject gains using the
> > standard CCS gain model, but those registers are said to be read-only
>
> The m[01] and c[01] factors in the CCS analogue gain formula are constants
> that determine how the sensor's analogue gain setting translates to actual
> analogue gain. They are not intended to be modifiable at runtime.
>
You're right sorry, indeed they're constant.
For this sensor:
analogue_gain_type: 0
analogue_gain_m0: 1
analogue_gain_c0: 0
analogue_gain_m1: 0
analogue_gain_c1: 4
I should be capable of programming the global analog gain using the linear
CCS gain model if the sensor is actually CCS compliant.
gain = m0 * x + c0 / m1 * x + c1
= R0x0204 / 4
However, the application developer guide shows the gain to be set
through manufacturer specific registers (0x3028 or 0x305e) and I cannot
find much correlations between the manufacturer specific gain model
(a piecewise exponential function) and the model described by CCS, which
seems way simpler.
> --
> Kind regards,
>
> Sakari Ailus
