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
332
Atmel | SMART SAM D20 [DATASHEET]
Atmel-42129K–SAM-D20_datasheet–06/2014
23.6.2 Basic Operation
23.6.2.1 Initialization
The SERCOM must be configured to the desired mode by writing to the Operating Mode bits in the Control A register
(CTRLA.MODE). Refer to Figure 23-1 for details.
Table 23-1. SERCOM Modes
For further initialization information, see the respective SERCOM mode chapters.
23.6.2.2 Enabling, Disabling and Resetting
The SERCOM is enabled by writing a one to the Enable bit in the Control A register (CTRLA.ENABLE). The SERCOM is
disabled by writing a zero to CTRLA.ENABLE.
The SERCOM is reset by writing a one to the Software Reset bit in the Control A register (CTRLA.SWRST). All registers
in the SERCOM, except DBGCTRL, will be reset to their initial state, and the SERCOM will be disabled. Refer to the
CTRLA register descriptions for details.
23.6.2.3 Clock Generation – Baud-Rate Generator
The baud-rate generator, as shown in Figure 23-3, is used for internal clock generation for asynchronous and
synchronous communication. The generated output frequency (f
BAUD
) is determined by the Baud register (BAUD) setting
and the baud reference frequency (f
REF
). The baud reference clock is the serial engine clock, and it can be internal or
external.
For asynchronous operation, the /16 (divide-by-16) output is used when transmitting and the /1 (divide-by-1) output is
used when receiving. For synchronous operation the /2 (divide-by-2) output is used. This functionality is automatically
configured, depending on the selected operating mode.
CTRLA.MODE Description
0x0 USART with external clock
0x1 USART with internal clock
0x2 SPI in slave operation
0x3 SPI in master operation
0x4 I
2
C slave operation
0x5 I
2
C master operation
0x6-0x7 Reserved