Datasheet

CY8C21x34/B CapSense
®
Design Guide Document No. 001-66271 Rev. *B 3
Contents
1. Introduction .................................................................................................................................................................... 7
1.1 Abstract ................................................................................................................................................................. 7
1.2 Cypress CapSense Documentation Ecosystem .................................................................................................... 7
1.3 CY8C21x34/B CapSense Plus Family Features.................................................................................................... 9
1.3.1 Advanced Touch Sensing Features .......................................................................................................... 9
1.3.2 Device Features........................................................................................................................................ 9
1.4 Document Conventions ....................................................................................................................................... 10
2. CapSense Technology ................................................................................................................................................ 11
2.1 CapSense Fundamentals .................................................................................................................................... 11
2.2 CapSense Methods in CY8C21x34/B .................................................................................................................. 13
2.2.1 CapSense with Sigma Delta Modulator (CSD) ....................................................................................... 13
2.2.2 CSD with ADC Functionality (CSDADC) ................................................................................................. 14
2.2.3 SmartSense™ Auto-tuning ..................................................................................................................... 14
3. CapSense Design Tools .............................................................................................................................................. 16
3.1 Overview of CapSense Design Tools .................................................................................................................. 16
3.1.1 PSoC Designer™ and User Modules ..................................................................................................... 16
3.1.2 Universal CapSense Controller Kit ......................................................................................................... 17
3.1.3 Universal CapSense Controller Module Board ....................................................................................... 18
3.1.4 CapSense Data Viewing Tools ............................................................................................................... 18
3.2 User Module Overview ........................................................................................................................................ 18
3.3 CapSense User Module Global Arrays ................................................................................................................ 18
3.3.1 Raw Count .............................................................................................................................................. 19
3.3.2 Baseline .................................................................................................................................................. 19
3.3.3 Difference Count (Signal) ....................................................................................................................... 19
3.3.4 Sensor State ........................................................................................................................................... 19
3.4 CSD User Module Configurations ........................................................................................................................ 20
3.4.1 CSD without Clock Prescaler .................................................................................................................. 20
3.4.2 CSD with Clock Prescaler ....................................................................................................................... 20
3.5 CSD User Module Parameters ............................................................................................................................ 20
3.6 CSD User Module High-Level Parameters .......................................................................................................... 21
3.6.1 Finger Threshold..................................................................................................................................... 21
3.6.2 Noise Threshold...................................................................................................................................... 21
3.6.3 Baseline Update Threshold .................................................................................................................... 21
3.6.4 Sensors Autoreset .................................................................................................................................. 21
3.6.5 Hysteresis ............................................................................................................................................... 21