For a touchkey matrix (without single electrode touchkeys), DxS allows only the first detected touch inside a group to be reported. By defining a DxS group with channel rows, and another group with channel columns, only one touchkey can be activated at a time. For an application managing only single touches, this simplifies the processing at the application level.
By following the guidelines described in this document it is possible to improve the touchkey capabilities of STM32 microcontrollers without modifying the touch sensing firmware library. The application software must determine which touchkey is touched when a pair of channels is activated, providinge a simple processing step.
| Date | Version | Changes |
|---|---|---|
| 18-Jun-2010 | 1 | Initial release. |
| 18-Nov-2013 | 2 | Added support for STM32F0, STM32F3, STM32L1, STM8AF series and STM8L162 lines. Updated:
Removed paragraph “Maximum touchkey matrix size by product”. |
| 28-May-2014 | 3 | Added support for STM32L0 series. |
| 3-Nov-2015 | 4 | Updated Table 1: STM32L4 series added (up to 24 channels) and STM8AL series added (up to 20 channels). |
| 17-Jan-2019 | 5 | Updated:
Added Section 1 General information. |
| 16-Mar-2020 | 6 | Updated Table 1. Applicable products |
| 10-Aug-2021 | 7 | Updated: |
| 27-Jan-2023 | 8 | Updated Introduction Added STM32WBA series in Table 1 |
| 06-Mar-2024 | 9 | Updated:
|
| 26-Nov-2024 | 10 | Updated:
|