Datasheet EFM8SB1 (Silicon Labs) - 7
| 制造商 | Silicon Labs |
| 描述 | EFM8 Sleepy Bee Family |
| 页数 / 页 | 71 / 7 — 3.4 Clocking. 3.5 Counters/Timers and PWM. Real Time Clock (RTC0). … |
| 文件格式/大小 | PDF / 1.2 Mb |
| 文件语言 | 英语 |
3.4 Clocking. 3.5 Counters/Timers and PWM. Real Time Clock (RTC0). Programmable Counter Array (PCA0). silabs.com
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EFM8SB1 Data Sheet System Overview
3.4 Clocking
The CPU core and peripheral subsystem may be clocked by both internal and external oscillator resources. By default, the system clock comes up running from the 20 MHz low power oscillator divided by 8. • Provides clock to core and peripherals. • 20 MHz low power oscillator (LPOSC0), accurate to ±10% over supply and temperature corners. • 24.5 MHz internal oscillator (HFOSC0), accurate to ±2% over supply and temperature corners. • 16.4 kHz low-frequency oscillator (LFOSC0) or external RTC 32 kHz crystal. • External RC, C, CMOS, and high-frequency crystal clock options (EXTCLK). • Clock divider with eight settings for flexible clock scaling: Divide the selected clock source by 1, 2, 4, 8, 16, 32, 64, or 128.
3.5 Counters/Timers and PWM Real Time Clock (RTC0)
The RTC is an ultra low power, 36 hour 32-bit independent time-keeping Real Time Clock with alarm. The RTC has a dedicated 32 kHz oscillator. No external resistor or loading capacitors are required, and a missing clock detector features alerts the system if the external crystal fails. The on-chip loading capacitors are programmable to 16 discrete levels allowing compatibility with a wide range of crystals. The RTC module includes the following features: • Up to 36 hours (32-bit) of independent time keeping. • Support for internal 16.4 kHz low frequency oscillator (LFOSC0) or external 32 kHz crystal (crystal not available on CSP16 pack- ages). • Internal crystal loading capacitors with 16 levels. • Operation in the lowest power mode and across the full supported voltage range. • Alarm and oscillator failure events to wake from the lowest power mode or reset the device. • Buffered clock output available for other system devices even in the lowest power mode.
Programmable Counter Array (PCA0)
The programmable counter array (PCA) provides multiple channels of enhanced timer and PWM functionality while requiring less CPU intervention than standard counter/timers. The PCA consists of a dedicated 16-bit counter/timer and one 16-bit capture/compare mod- ule for each channel. The counter/timer is driven by a programmable timebase that has flexible external and internal clocking options. Each capture/compare module may be configured to operate independently in one of five modes: Edge-Triggered Capture, Software Timer, High-Speed Output, Frequency Output, or Pulse-Width Modulated (PWM) Output. Each capture/compare module has its own associated I/O line (CEXn) which is routed through the crossbar to port I/O when enabled. • 16-bit time base. • Programmable clock divisor and clock source selection. • Up to three independently-configurable channels • 8, 9, 10, 11 and 16-bit PWM modes (edge-aligned operation). • Frequency output mode. • Capture on rising, falling or any edge. • Compare function for arbitrary waveform generation. • Software timer (internal compare) mode. • Integrated watchdog timer.
silabs.com
| Building a more connected world. Rev. 1.4 | 6 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
3.4 Clocking
The CPU core and peripheral subsystem may be clocked by both internal and external oscillator resources. By default, the system clock comes up running from the 20 MHz low power oscillator divided by 8. • Provides clock to core and peripherals. • 20 MHz low power oscillator (LPOSC0), accurate to ±10% over supply and temperature corners. • 24.5 MHz internal oscillator (HFOSC0), accurate to ±2% over supply and temperature corners. • 16.4 kHz low-frequency oscillator (LFOSC0) or external RTC 32 kHz crystal. • External RC, C, CMOS, and high-frequency crystal clock options (EXTCLK). • Clock divider with eight settings for flexible clock scaling: Divide the selected clock source by 1, 2, 4, 8, 16, 32, 64, or 128.
3.5 Counters/Timers and PWM Real Time Clock (RTC0)
The RTC is an ultra low power, 36 hour 32-bit independent time-keeping Real Time Clock with alarm. The RTC has a dedicated 32 kHz oscillator. No external resistor or loading capacitors are required, and a missing clock detector features alerts the system if the external crystal fails. The on-chip loading capacitors are programmable to 16 discrete levels allowing compatibility with a wide range of crystals. The RTC module includes the following features: • Up to 36 hours (32-bit) of independent time keeping. • Support for internal 16.4 kHz low frequency oscillator (LFOSC0) or external 32 kHz crystal (crystal not available on CSP16 pack- ages). • Internal crystal loading capacitors with 16 levels. • Operation in the lowest power mode and across the full supported voltage range. • Alarm and oscillator failure events to wake from the lowest power mode or reset the device. • Buffered clock output available for other system devices even in the lowest power mode.
Programmable Counter Array (PCA0)
The programmable counter array (PCA) provides multiple channels of enhanced timer and PWM functionality while requiring less CPU intervention than standard counter/timers. The PCA consists of a dedicated 16-bit counter/timer and one 16-bit capture/compare mod- ule for each channel. The counter/timer is driven by a programmable timebase that has flexible external and internal clocking options. Each capture/compare module may be configured to operate independently in one of five modes: Edge-Triggered Capture, Software Timer, High-Speed Output, Frequency Output, or Pulse-Width Modulated (PWM) Output. Each capture/compare module has its own associated I/O line (CEXn) which is routed through the crossbar to port I/O when enabled. • 16-bit time base. • Programmable clock divisor and clock source selection. • Up to three independently-configurable channels • 8, 9, 10, 11 and 16-bit PWM modes (edge-aligned operation). • Frequency output mode. • Capture on rising, falling or any edge. • Compare function for arbitrary waveform generation. • Software timer (internal compare) mode. • Integrated watchdog timer.
silabs.com
| Building a more connected world. Rev. 1.4 | 6 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