Datasheet EFM8SB1 (Silicon Labs) - 10
| Manufacturer | Silicon Labs |
| Description | EFM8 Sleepy Bee Family |
| Pages / Page | 71 / 10 — 3.7 Analog. Capacitive Sense (CS0). Programmable Current Reference … |
| File Format / Size | PDF / 1.2 Mb |
| Document Language | English |
3.7 Analog. Capacitive Sense (CS0). Programmable Current Reference (IREF0). 12-Bit Analog-to-Digital Converter (ADC0)
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EFM8SB1 Data Sheet System Overview
3.7 Analog Capacitive Sense (CS0)
The Capacitive Sense subsystem uses a capacitance-to-digital circuit to determine the capacitance on a port pin. The module can take measurements from different port pins using the module’s analog multiplexer. The module can be configured to take measurements on one port pin, a group of port pins one-by-one using auto-scan, or the total capacitance on multiple channels together. A selectable gain circuit allows the designer to adjust the maximum allowable capacitance. An accumulator is also included, which can be configured to average multiple conversions on an input channel. Interrupts can be generated when the CS0 peripheral completes a conversion or when the measured value crosses a configurable threshold. The Capacitive Sense module includes the following features: • Measure multiple pins one-by-one using auto-scan or total capacitance on multiple channels together. • Configurable input gain. • Hardware auto-accumulate and average. • Multiple internal start-of-conversion sources. • Operational in Suspend when all other clocks are disabled. • Interrupts available at the end of a conversion or when the measured value crosses a configurable threshold.
Programmable Current Reference (IREF0)
The programmable current reference (IREF0) module enables current source or sink with two output current settings: Low Power Mode and High Current Mode. The maximum current output in Low Power Mode is 63 µA (1 µA steps) and the maximum current output in High Current Mode is 504 µA (8 µA steps). The IREF module includes the following features: • Capable of sourcing or sinking current in programmable steps. • Two operational modes: Low Power Mode and High Current Mode. • Fine-tuning mode for higher output precision available in conjunction with the PCA0 module.
12-Bit Analog-to-Digital Converter (ADC0)
The ADC is a successive-approximation-register (SAR) ADC with 12-, 10-, and 8-bit modes, integrated track-and hold and a program- mable window detector. The ADC is fully configurable under software control via several registers. The ADC may be configured to measure different signals using the analog multiplexer. The voltage reference for the ADC is selectable between internal and external reference sources. • Up to 10 external inputs. • Single-ended 12-bit and 10-bit modes. • Supports an output update rate of 75 ksps samples per second in 12-bit mode or 300 ksps samples per second in 10-bit mode. • Operation in low power modes at lower conversion speeds. • Asynchronous hardware conversion trigger, selectable between software, external I/O and internal timer sources. • Output data window comparator allows automatic range checking. • Support for burst mode, which produces one set of accumulated data per conversion-start trigger with programmable power-on set- tling and tracking time. • Conversion complete and window compare interrupts supported. • Flexible output data formatting. • Includes an internal 1.65 V fast-settling reference and support for external reference. • Integrated temperature sensor.
silabs.com
| Building a more connected world. Rev. 1.4 | 9 Document Outline 1. Feature List 2. Ordering Information 3. System Overview 3.1 Introduction 3.2 Power 3.3 I/O 3.4 Clocking 3.5 Counters/Timers and PWM 3.6 Communications and Other Digital Peripherals 3.7 Analog 3.8 Reset Sources 3.9 Debugging 3.10 Bootloader 4. Electrical Specifications 4.1 Electrical Characteristics 4.1.1 Recommended Operating Conditions 4.1.2 Power Consumption 4.1.3 Reset and Supply Monitor 4.1.4 Flash Memory 4.1.5 Power Management Timing 4.1.6 Internal Oscillators 4.1.7 Crystal Oscillator 4.1.8 External Clock Input 4.1.9 ADC 4.1.10 Voltage Reference 4.1.11 Temperature Sensor 4.1.12 Comparators 4.1.13 Programmable Current Reference (IREF0) 4.1.14 Capacitive Sense (CS0) 4.1.15 Port I/O 4.1.16 SMBus 4.2 Thermal Conditions 4.3 Absolute Maximum Ratings 4.4 Typical Performance Curves 5. Typical Connection Diagrams 5.1 Power 5.2 Debug 5.3 Other Connections 6. Pin Definitions 6.1 EFM8SB1x-QFN20 Pin Definitions 6.2 EFM8SB1x-QFN24 Pin Definitions 6.3 EFM8SB1x-QSOP24 Pin Definitions 6.4 EFM8SB1x-CSP16 Pin Definitions 7. CSP16 Package Specifications 7.1 CSP16 Package Dimensions 7.2 CSP16 PCB Land Pattern 7.3 CSP16 Package Marking 8. QFN20G Package Specifications 8.1 QFN20 Package Dimensions 8.2 QFN20 PCB Land Pattern 8.3 QFN20 Package Marking 9. QFN20A Package Specifications 9.1 QFN20 Package Dimensions 9.2 QFN20 PCB Land Pattern 9.3 QFN20 Package Marking 10. QFN24 Package Specifications 10.1 QFN24 Package Dimensions 10.2 QFN24 PCB Land Pattern 10.3 QFN24 Package Marking 11. QSOP24 Package Specifications 11.1 QSOP24 Package Dimensions 11.2 QSOP24 PCB Land Pattern 11.3 QSOP24 Package Marking 12. Revision History 12.1 Revision 1.4 12.2 Revision 1.3 12.3 Revision 1.2 12.4 Revision 1.1 Table of Contents
3.7 Analog Capacitive Sense (CS0)
The Capacitive Sense subsystem uses a capacitance-to-digital circuit to determine the capacitance on a port pin. The module can take measurements from different port pins using the module’s analog multiplexer. The module can be configured to take measurements on one port pin, a group of port pins one-by-one using auto-scan, or the total capacitance on multiple channels together. A selectable gain circuit allows the designer to adjust the maximum allowable capacitance. An accumulator is also included, which can be configured to average multiple conversions on an input channel. Interrupts can be generated when the CS0 peripheral completes a conversion or when the measured value crosses a configurable threshold. The Capacitive Sense module includes the following features: • Measure multiple pins one-by-one using auto-scan or total capacitance on multiple channels together. • Configurable input gain. • Hardware auto-accumulate and average. • Multiple internal start-of-conversion sources. • Operational in Suspend when all other clocks are disabled. • Interrupts available at the end of a conversion or when the measured value crosses a configurable threshold.
Programmable Current Reference (IREF0)
The programmable current reference (IREF0) module enables current source or sink with two output current settings: Low Power Mode and High Current Mode. The maximum current output in Low Power Mode is 63 µA (1 µA steps) and the maximum current output in High Current Mode is 504 µA (8 µA steps). The IREF module includes the following features: • Capable of sourcing or sinking current in programmable steps. • Two operational modes: Low Power Mode and High Current Mode. • Fine-tuning mode for higher output precision available in conjunction with the PCA0 module.
12-Bit Analog-to-Digital Converter (ADC0)
The ADC is a successive-approximation-register (SAR) ADC with 12-, 10-, and 8-bit modes, integrated track-and hold and a program- mable window detector. The ADC is fully configurable under software control via several registers. The ADC may be configured to measure different signals using the analog multiplexer. The voltage reference for the ADC is selectable between internal and external reference sources. • Up to 10 external inputs. • Single-ended 12-bit and 10-bit modes. • Supports an output update rate of 75 ksps samples per second in 12-bit mode or 300 ksps samples per second in 10-bit mode. • Operation in low power modes at lower conversion speeds. • Asynchronous hardware conversion trigger, selectable between software, external I/O and internal timer sources. • Output data window comparator allows automatic range checking. • Support for burst mode, which produces one set of accumulated data per conversion-start trigger with programmable power-on set- tling and tracking time. • Conversion complete and window compare interrupts supported. • Flexible output data formatting. • Includes an internal 1.65 V fast-settling reference and support for external reference. • Integrated temperature sensor.
silabs.com
| Building a more connected world. Rev. 1.4 | 9 Document Outline 1. Feature List 2. Ordering Information 3. System Overview 3.1 Introduction 3.2 Power 3.3 I/O 3.4 Clocking 3.5 Counters/Timers and PWM 3.6 Communications and Other Digital Peripherals 3.7 Analog 3.8 Reset Sources 3.9 Debugging 3.10 Bootloader 4. Electrical Specifications 4.1 Electrical Characteristics 4.1.1 Recommended Operating Conditions 4.1.2 Power Consumption 4.1.3 Reset and Supply Monitor 4.1.4 Flash Memory 4.1.5 Power Management Timing 4.1.6 Internal Oscillators 4.1.7 Crystal Oscillator 4.1.8 External Clock Input 4.1.9 ADC 4.1.10 Voltage Reference 4.1.11 Temperature Sensor 4.1.12 Comparators 4.1.13 Programmable Current Reference (IREF0) 4.1.14 Capacitive Sense (CS0) 4.1.15 Port I/O 4.1.16 SMBus 4.2 Thermal Conditions 4.3 Absolute Maximum Ratings 4.4 Typical Performance Curves 5. Typical Connection Diagrams 5.1 Power 5.2 Debug 5.3 Other Connections 6. Pin Definitions 6.1 EFM8SB1x-QFN20 Pin Definitions 6.2 EFM8SB1x-QFN24 Pin Definitions 6.3 EFM8SB1x-QSOP24 Pin Definitions 6.4 EFM8SB1x-CSP16 Pin Definitions 7. CSP16 Package Specifications 7.1 CSP16 Package Dimensions 7.2 CSP16 PCB Land Pattern 7.3 CSP16 Package Marking 8. QFN20G Package Specifications 8.1 QFN20 Package Dimensions 8.2 QFN20 PCB Land Pattern 8.3 QFN20 Package Marking 9. QFN20A Package Specifications 9.1 QFN20 Package Dimensions 9.2 QFN20 PCB Land Pattern 9.3 QFN20 Package Marking 10. QFN24 Package Specifications 10.1 QFN24 Package Dimensions 10.2 QFN24 PCB Land Pattern 10.3 QFN24 Package Marking 11. QSOP24 Package Specifications 11.1 QSOP24 Package Dimensions 11.2 QSOP24 PCB Land Pattern 11.3 QSOP24 Package Marking 12. Revision History 12.1 Revision 1.4 12.2 Revision 1.3 12.3 Revision 1.2 12.4 Revision 1.1 Table of Contents
