Datasheet
Table Of Contents
- Description
- Features
- 1. Configuration Summary
- 2. Ordering Information
- 3. Block Diagram
- 4. Pinout
- 5. I/O Multiplexing and Considerations
- 6. Signal Descriptions List
- 7. Power Supply and Start-Up Considerations
- 8. Product Mapping
- 9. Memories
- 10. Processor and Architecture
- 11. Peripherals Configuration Overview
- 12. DSU – Device Service Unit
- 12.1 Overview
- 12.2 Features
- 12.3 Block Diagram
- 12.4 Signal Description
- 12.5 Product Dependencies
- 12.6 Debug Operation
- 12.7 Chip-Erase
- 12.8 Programming
- 12.9 Intellectual Property Protection
- 12.10 Device Identification
- 12.11 Functional Description
- 12.12 Register Summary
- 12.13 Register Description
- 12.13.1 Control
- 12.13.2 Status A
- 12.13.3 Status B
- 12.13.4 Address
- 12.13.5 Length
- 12.13.6 Data
- 12.13.7 Debug Communication Channel n
- 12.13.8 Device Identification
- 12.13.9 CoreSight ROM Table Entry n
- 12.13.10 CoreSight ROM Table End
- 12.13.11 Coresight ROM Table Memory Type
- 12.13.12 Peripheral Identification 4
- 12.13.13 Peripheral Identification 0
- 12.13.14 Peripheral Identification 1
- 12.13.15 Peripheral Identification 2
- 12.13.16 Peripheral Identification 3
- 12.13.17 Component Identification 0
- 12.13.18 Component Identification 1
- 12.13.19 Component Identification 2
- 12.13.20 Component Identification 3
- 13. Clock System
- 14. GCLK – Generic Clock Controller
- 14.1 Overview
- 14.2 Features
- 14.3 Block Diagram
- 14.4 Signal Description
- 14.5 Product Dependencies
- 14.6 Functional Description
- 14.6.1 Principle of Operation
- 14.6.2 Basic Operation
- 14.6.2.1 Initialization
- 14.6.2.2 Enabling, Disabling and Resetting
- 14.6.2.3 Generic Clock Generator
- 14.6.2.4 Enabling a Generic Clock Generator
- 14.6.2.5 Disabling a Generic Clock Generator
- 14.6.2.6 Selecting a Clock Source for the Generic Clock Generator
- 14.6.2.7 Changing Clock Frequency
- 14.6.2.8 Duty Cycle
- 14.6.2.9 Generic Clock Output on I/O Pins
- 14.6.3 Generic Clock
- 14.6.4 Additional Features
- 14.6.5 Sleep Mode Operation
- 14.6.6 Synchronization
- 14.7 Register Summary
- 14.8 Register Description
- 15. PM – Power Manager
- 15.1 Overview
- 15.2 Features
- 15.3 Block Diagram
- 15.4 Signal Description
- 15.5 Product Dependencies
- 15.6 Functional Description
- 15.6.1 Principle of Operation
- 15.6.2 Basic Operation
- 15.6.2.1 Initialization
- 15.6.2.2 Enabling, Disabling and Resetting
- 15.6.2.3 Selecting the Main Clock Source
- 15.6.2.4 Selecting the Synchronous Clock Division Ratio
- 15.6.2.5 Clock Ready Flag
- 15.6.2.6 Peripheral Clock Masking
- 15.6.2.7 Clock Failure Detector
- 15.6.2.8 Reset Controller
- 15.6.2.9 Sleep Mode Controller
- 15.6.3 SleepWalking
- 15.6.4 Interrupts
- 15.6.5 Events
- 15.6.6 Sleep Mode Operation
- 15.7 Register Summary
- 15.8 Register Description
- 15.8.1 Control
- 15.8.2 Sleep Mode
- 15.8.3 CPU Clock Select
- 15.8.4 APBA Clock Select
- 15.8.5 APBB Clock Select
- 15.8.6 APBC Clock Select
- 15.8.7 AHB Mask
- 15.8.8 APBA Mask
- 15.8.9 APBB Mask
- 15.8.10 APBC Mask
- 15.8.11 Interrupt Enable Clear
- 15.8.12 Interrupt Enable Set
- 15.8.13 Interrupt Flag Status and Clear
- 15.8.14 Reset Cause
- 16. SYSCTRL – System Controller
- 16.1 Overview
- 16.2 Features
- 16.3 Block Diagram
- 16.4 Signal Description
- 16.5 Product Dependencies
- 16.6 Functional Description
- 16.6.1 Principle of Operation
- 16.6.2 External Multipurpose Crystal Oscillator (XOSC) Operation
- 16.6.3 32kHz External Crystal Oscillator (XOSC32K) Operation
- 16.6.4 32kHz Internal Oscillator (OSC32K) Operation
- 16.6.5 32kHz Ultra Low Power Internal Oscillator (OSCULP32K) Operation
- 16.6.6 8MHz Internal Oscillator (OSC8M) Operation
- 16.6.7 Digital Frequency Locked Loop (DFLL48M) Operation
- 16.6.8 3.3V Brown-Out Detector Operation
- 16.6.9 Voltage Reference System Operation
- 16.6.10 Interrupts
- 16.6.11 Synchronization
- 16.7 Register Summary
- 16.8 Register Description
- 16.8.1 Interrupt Enable Clear
- 16.8.2 Interrupt Enable Set
- 16.8.3 Interrupt Flag Status and Clear
- 16.8.4 Power and Clocks Status
- 16.8.5 External Multipurpose Crystal Oscillator (XOSC) Control
- 16.8.6 32kHz External Crystal Oscillator (XOSC32K) Control
- 16.8.7 32kHz Internal Oscillator (OSC32K) Control
- 16.8.8 32kHz Ultra Low Power Internal Oscillator (OSCULP32K) Control
- 16.8.9 8MHz Internal Oscillator (OSC8M) Control
- 16.8.10 DFLL48M Control
- 16.8.11 DFLL48M Value
- 16.8.12 DFLL48M Multiplier
- 16.8.13 DFLL48M Synchronization
- 16.8.14 3.3V Brown-Out Detector (BOD33) Control
- 16.8.15 Voltage Regulator System (VREG) Control
- 16.8.16 Voltage References System (VREF) Control
- 17. WDT – Watchdog Timer
- 18. RTC – Real-Time Counter
- 18.1 Overview
- 18.2 Features
- 18.3 Block Diagram
- 18.4 Signal Description
- 18.5 Product Dependencies
- 18.6 Functional Description
- 18.7 Register Summary
- 18.8 Register Description
- 18.8.1 Control
- 18.8.2 Read Request
- 18.8.3 Event Control
- 18.8.4 Interrupt Enable Clear
- 18.8.5 Interrupt Enable Set
- 18.8.6 Interrupt Flag Status and Clear
- 18.8.7 Status
- 18.8.8 Debug Control
- 18.8.9 Frequency Correction
- 18.8.10 Counter Value
- 18.8.11 Clock Value
- 18.8.12 Counter Period
- 18.8.13 Compare n Value
- 18.8.14 Alarm n Value
- 18.8.15 Alarm n Mask
- 19. EIC – External Interrupt Controller
- 20. NVMCTRL – Non-Volatile Memory Controller
- 20.1 Overview
- 20.2 Features
- 20.3 Block Diagram
- 20.4 Signal Description
- 20.5 Product Dependencies
- 20.6 Functional Description
- 20.7 Register Summary
- 20.8 Register Description
- 21. PORT
- 21.1 Overview
- 21.2 Features
- 21.3 Block Diagram
- 21.4 Signal Description
- 21.5 Product Dependencies
- 21.6 Functional Description
- 21.7 Register Summary
- 21.8 Register Description
- 21.8.1 Data Direction
- 21.8.2 Data Direction Clear
- 21.8.3 Data Direction Set
- 21.8.4 Data Direction Toggle
- 21.8.5 Data Output Value
- 21.8.6 Data Output Value Clear
- 21.8.7 Data Output Value Set
- 21.8.8 Data Output Value Toggle
- 21.8.9 Data Input Value
- 21.8.10 Control
- 21.8.11 Write Configuration
- 21.8.12 Peripheral Multiplexing n
- 21.8.13 Pin Configuration y
- 22. EVSYS – Event System
- 23. SERCOM – Serial Communication Interface
- 24. SERCOM USART – SERCOM Universal Synchronous and Asynchronous Receiver and Transmitter
- 24.1 Overview
- 24.2 Features
- 24.3 Block Diagram
- 24.4 Signal Description
- 24.5 Product Dependencies
- 24.6 Functional Description
- 24.7 Register Summary
- 24.8 Register Description
- 25. SERCOM SPI – SERCOM Serial Peripheral Interface
- 25.1 Overview
- 25.2 Features
- 25.3 Block Diagram
- 25.4 Signal Description
- 25.5 Product Dependencies
- 25.6 Functional Description
- 25.7 Register Summary
- 25.8 Register Description
- 26. SERCOM I2C – SERCOM Inter-Integrated Circuit
- 26.1 Overview
- 26.2 Features
- 26.3 Block Diagram
- 26.4 Signal Description
- 26.5 Product Dependencies
- 26.6 Functional Description
- 26.7 Register Summary
- 26.8 Register Description
- 27. TC – Timer/Counter
- 27.1 Overview
- 27.2 Features
- 27.3 Block Diagram
- 27.4 Signal Description
- 27.5 Product Dependencies
- 27.6 Functional Description
- 27.7 Register Summary
- 27.8 Register Description
- 27.8.1 Control A
- 27.8.2 Read Request
- 27.8.3 Control B Clear
- 27.8.4 Control B Set
- 27.8.5 Control C
- 27.8.6 Debug Control
- 27.8.7 Event Control
- 27.8.8 Interrupt Enable Clear
- 27.8.9 Interrupt Enable Set
- 27.8.10 Interrupt Flag Status and Clear
- 27.8.11 Status
- 27.8.12 Counter Value
- 27.8.13 Period Value
- 27.8.14 Compare/Capture
- 28. ADC – Analog-to-Digital Converter
- 28.1 Overview
- 28.2 Features
- 28.3 Block Diagram
- 28.4 Signal Description
- 28.5 Product Dependencies
- 28.6 Functional Description
- 28.6.1 Principle of Operation
- 28.6.2 Basic Operation
- 28.6.3 Prescaler
- 28.6.4 ADC Resolution
- 28.6.5 Differential and Single-Ended Conversions
- 28.6.6 Accumulation
- 28.6.7 Averaging
- 28.6.8 Oversampling and Decimation
- 28.6.9 Window Monitor
- 28.6.10 Offset and Gain Correction
- 28.6.11 Interrupts
- 28.6.12 Events
- 28.6.13 Sleep Mode Operation
- 28.6.14 Synchronization
- 28.7 Register Summary
- 28.8 Register Description
- 28.8.1 Control A
- 28.8.2 Reference Control
- 28.8.3 Average Control
- 28.8.4 Sampling Time Control
- 28.8.5 Control B
- 28.8.6 Window Monitor Control
- 28.8.7 Software Trigger
- 28.8.8 Input Control
- 28.8.9 Event Control
- 28.8.10 Interrupt Enable Clear
- 28.8.11 Interrupt Enable Set
- 28.8.12 Interrupt Flag Status and Clear
- 28.8.13 Status
- 28.8.14 Result
- 28.8.15 Window Monitor Lower Threshold
- 28.8.16 Window Monitor Upper Threshold
- 28.8.17 Gain Correction
- 28.8.18 Offset Correction
- 28.8.19 Calibration
- 28.8.20 Debug Control
- 29. AC – Analog Comparators
- 29.1 Overview
- 29.2 Features
- 29.3 Block Diagram
- 29.4 Signal Description
- 29.5 Product Dependencies
- 29.6 Functional Description
- 29.7 Additional Features
- 29.8 Register Summary
- 29.9 Register Description
- 30. DAC – Digital-to-Analog Converter
- 30.1 Overview
- 30.2 Features
- 30.3 Block Diagram
- 30.4 Signal Description
- 30.5 Product Dependencies
- 30.6 Functional Description
- 30.7 Register Summary
- 30.8 Register Description
- 31. PTC - Peripheral Touch Controller
- 32. Electrical Characteristics
- 32.1 Disclaimer
- 32.2 Absolute Maximum Ratings
- 32.3 General Operating Ratings
- 32.4 Supply Characteristics
- 32.5 Maximum Clock Frequencies
- 32.6 Power Consumption
- 32.7 I/O Pin Characteristics
- 32.8 Analog Characteristics
- 32.8.1 Voltage Regulator Characteristics
- 32.8.2 Power-On Reset (POR) Characteristics
- 32.8.3 Brown-Out Detectors Characteristics
- 32.8.4 Analog-to-Digital (ADC) characteristics
- 32.8.5 Digital to Analog Converter (DAC) Characteristics
- 32.8.6 Analog Comparator Characteristics
- 32.8.7 Bandgap Reference Characteristics
- 32.8.8 Temperature Sensor Characteristics
- 32.9 NVM Characteristics
- 32.10 Oscillators Characteristics
- 32.10.1 Crystal Oscillator (XOSC) Characteristics
- 32.10.2 External 32 kHz Crystal Oscillator (XOSC32K) Characteristics
- 32.10.3 Digital Frequency Locked Loop (DFLL48M) Characteristics
- 32.10.4 32.768kHz Internal oscillator (OSC32K) Characteristics
- 32.10.5 Ultra Low Power Internal 32kHz RC Oscillator (OSCULP32K) Characteristics
- 32.10.6 8MHz RC Oscillator (OSC8M) Characteristics
- 32.11 PTC Typical Characteristics
- 32.12 Timing Characteristics
- 33. Packaging Information
- 34. Schematic Checklist
- 35. Errata
- 36. Datasheet Revision History
- Appendix A. Conventions
- Appendix B. Acronyms and Abbreviations
- Table of Contents
613
Atmel | SMART SAM D20 [DATASHEET]
Atmel-42129K–SAM-D20_datasheet–06/2014
2. Decoupling capacitor should be placed close to the device for each supply pin pair in the signal group.
34.6.3 External Real Time Oscillator
The low frequency crystal oscillator is optimized for use with a 32.768kHz watch crystal. When selecting crystals, load
capacitance and crystal’s Equivalent Series Resistance (ESR) must be taken into consideration. Both values are
specified by the crystal vendor
.
SAM D20 oscillator is optimized for very low power consumption, hence close attention should be made when selecting
crystals, see Table 34-6 for maximum ESR recommendations on 9pF and 12.5pF crystals
.
The Low-frequency Crystal Oscillator provides an internal load capacitance of typical 3.05pF and 3.29pF. Crystals with
recommended 12.5pF load capacitance can be without external capacitors as shown in Figure 34-7.
Note: Maximum ESR is typical value based on characterization. These values are not covered by test limits in
production.
Figure 34-7. External Real Time Oscillator without Load Capacitor
Crystals specifying load capacitance (CL) higher than 12.5pF, require external capacitors applied as described in Figure
34-8.
To find suitable load capacitance for a 32.768kHz crystal, consult the crystal datasheet.
Figure 34-8. External Real Time Oscillator with Load Capacitor
Notes: 1. These values are given only as typical examples.
2. Decoupling capacitor should be placed close to the device for each supply pin pair in the signal group.
Table 34-6. Maximum ESR Recommendation for 32.768kHz Crystal
Crystal C
L
(pF) Max ESR [kΩ]
12.5 313
Table 34-7. External Real Time Oscillator Checklist
Signal Name Recommended Pin Connection Description
XIN32 Load capacitor 22pF
(1)(2)
Timer oscillator input
XOUT32 Load capacitor 22pF
(1)(2)
Timer oscillator output
XOUT32
XIN32
32.768kHz
XOUT32
XIN32
32.768kHz
22pF
22pF