6.10.14 CapTIvate Technology
The CapTIvate module measures changes in the capacitance of a sensing electrode with a charge-transfer measurement method. It is functional in AM, LPM0, LPM3, and LPM4. The CapTIvate module can periodically wake the CPU from LPM0, LPM3, or LPM4 based on a CapTIvate timer source such as ACLK or VLO clock. The CapTIvate module supports the following touch-sensing capability:
- 16 CapTIvate I/Os supporting up to 16 electrodes in self-capacitance mode or 64 electrodes in mutual-capacitance mode
- 4 CapTIvate measurement blocks to enable parallel scanning of up to 4 electrodes simultaneously (one electrode per block)
- Each CapTIvate block can be individually configured in self or mutual mode, and each CapTIvate I/O can be used for either self or mutual capacitance electrodes.
- Support synchronizing the start of a conversion to an external trigger, such as a zero-crossing event
- Includes a wake-on-touch state machine with processing logic to perform filter calculations and threshold detection
- Includes hardware accelerated oversampling and frequency hopping to enable reduced CPU loading in applications that require noise immunity
- Noise-attenuating charge transfer circuit with adjustable input impedance enabling robustness in the presence of conducted and radiated noise with low CPU post-processing requirements
- Selectable electrode charge voltage (DVCC or CapTIvate VREG), allowing the designer to optimize for high sensitivity in the presence of conducted and radiated noise or stability across DVCC supply voltage variation
- Adjustable on-chip sampling capacitor size to support calibration of low-capacitance electrodes
To learn more about MSP MCUs featuring CapTIvate™ technology, see the CapTIvate™ Technology Guide.