With regards to PCA2131 & PCF2131TF, what are the minimum time that the TS signals have to be low for it to be detected ? I can't find it in the data-sheet.
I suppose the level have to be 0.3VDD, or lower, as it's an Input.
The TS1–TS4 pins are indeed active LOW inputs with an internal 500k pull-up resistor. The input voltage thresholds are: VIL: ≤ 0.3 × VDD, VIH: ≥ 0.7 × VDD. To ensure reliable detection, I suggest keeping the TS input LOW for at least 100 ms.
