3.3.5 Steps To Configure Measurement Clock Frequency and CSD

Following are the steps for tuning CSD:

1. Start with a higher CSD value, e.g. 30, and observe the touch delta.
2. Observe the Delta with CSD-values 25, 20, 15, 10, 5 and zero.
3. From these values, find the CSD for which the delta is not significantly less compared to the delta with a CSD of 30.
4. Use that CSD value.

In this example, the highest delta value of 40 is found with a CSD value of 15. Increasing CSD beyond 15 does not help to increase the delta. So, it is better to use CSD = 15. It is possible to finetune CSD by comparing the delta with CSD 14, 13, 12, and 11.

Use higher values than the values resulting from the tune to take tolerance into account. In the case of CSD, use a 20% higher value. For example: If the tuned CSD value is 10, use 12.

For most applications, the maximum 1 MHz measurement clock frequency works well along with fine tuning of CSD. Only when using maximum CSD at max Touch Acquisition Frequency doesn't lead to maximum delta, reducing the measurement clock frequency can be tried.