On Sun, Aug 30, 2026 at 12:03:29PM -0300, Marcelo Schmitt wrote:
> Having a closer look at the data sheet I found for STK36C61, I noticed
> registers
> 0x13 and 0x14 are not listed. Does the newer part has ambient light sensing
> besides the clear channel?
That looks to be the "STK36C61-A Preliminary Datasheet v0.9" hosted by
LCSC [1], which I hadn't found before, so the cover letter's "There is
no public datasheet" is wrong. It documents the -A variant, however,
and gives PDT_ID as 0x93, while the part in the Fairphone 6 reports
0x95. It does agree with the device on the colour-engine layout: RGBC
data at 0x15-0x1C, a clear-channel gain in GAINCTRL 0x4E, and the
shared GAIN_RGB/IT_ALS fields in ALSCTRL1.
Yes, there is ambient light sensing besides the clear channel:
0x13/0x14 are present on this device despite their absence from the
datasheet map. They behave exactly like the stk3310's ALS data
registers and are what the illuminance channel reads. The ALS word
tracks the green channel exactly, proven by the x16 gain step moving
both from 25 to 404. The sheet's own text does describe the function:
it defines DATA_ALS[15:0] ("16-bits ALS channel raw data"), windows it
with the THDH/THDL_ALS thresholds at 0x0A-0x0D, and calls FLG_ALS_INT
"the Green channel out-of-windows event", which is consistent with the
ALS == green behaviour I measured.
[1] https://www.lcsc.com/datasheet/C49230205.pdf
Thanks,
Jorijn
