Datasheet

ManualsBrandsMICROCHIP TECHNOLOGY ManualsDev KitsPCB design board

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Table Of Contents

Description
Features
1. Configuration Summary
2. Ordering Information
- 2.1 SAM D20E
- 2.2 SAM D20G
- 2.3 SAM D20J
3. Block Diagram
4. Pinout
- 4.1 SAM D20J
- 4.2 SAM D20G
- 4.3 SAM D20E
5. I/O Multiplexing and Considerations
- 5.1 Multiplexed Signals
- 5.2 Other Functions
  - 5.2.1 Oscillator Pinout
  - 5.2.2 Serial Wire Debug Interface Pinout
6. Signal Descriptions List
7. Power Supply and Start-Up Considerations
- 7.1 Power Domain Overview
- 7.2 Power Supply Considerations
- 7.3 Power-Up
- 7.4 Power-On Reset and Brown-Out Detector
8. Product Mapping
9. Memories
- 9.1 Embedded Memories
- 9.2 Physical Memory Map
- 9.3 Non-Volatile Memory (NVM) User Row Mapping
- 9.4 NVM Software Calibration Area Mapping
- 9.5 Serial Number
10. Processor and Architecture
- 10.1 Cortex-M0+ Processor
- 10.2 Nested Vector Interrupt Controller
  - 10.2.1 Overview
  - 10.2.2 Interrupt Line Mapping
- 10.3 High-Speed Bus Matrix
  - 10.3.1 Features
  - 10.3.2 Configuration
- 10.4 AHB-APB Bridge
- 10.5 PAC – Peripheral Access Controller
  - 10.5.1 Overview
- 10.6 Register Description
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
  - 12.10.1 CoreSight Identification
  - 12.10.2 DSU Chip Identification Method:
- 12.11 Functional Description
- 12.12 Register Summary
- 12.13 Register Description
13. Clock System
- 13.1 Clock Distribution
- 13.2 Synchronous and Asynchronous Clocks
- 13.3 Register Synchronization
- 13.4 Enabling a Peripheral
- 13.5 On-demand, Clock Requests
- 13.6 Power Consumption vs Speed
- 13.7 Clocks after Reset
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
- 14.7 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
- 15.7 Register Summary
- 15.8 Register Description
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
- 16.7 Register Summary
- 16.8 Register Description
17. WDT – Watchdog Timer
- 17.1 Overview
- 17.2 Features
- 17.3 Block Diagram
- 17.4 Signal Description
- 17.5 Product Dependencies
- 17.6 Functional Description
- 17.7 Register Summary
- 17.8 Register Description
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
19. EIC – External Interrupt Controller
- 19.1 Overview
- 19.2 Features
- 19.3 Block Diagram
- 19.4 Signal Description
- 19.5 Product Dependencies
- 19.6 Functional Description
- 19.7 Register Summary
- 19.8 Register Description
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
22. EVSYS – Event System
- 22.1 Overview
- 22.2 Features
- 22.3 Block Diagram
- 22.4 Signal Description
- 22.5 Product Dependencies
- 22.6 Functional Description
- 22.7 Register Summary
- 22.8 Register Description
23. SERCOM – Serial Communication Interface
- 23.1 Overview
- 23.2 Features
- 23.3 Block Diagram
- 23.4 Signal Description
- 23.5 Product Dependencies
- 23.6 Functional Description
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
  - 26.8.1 I2C Slave Register Description
  - 26.8.2 I2C Master 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
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
- 28.7 Register Summary
- 28.8 Register Description
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
- 31.1 Overview
- 31.2 Features
- 31.3 Block Diagram
- 31.4 Signal Description
- 31.5 Product Dependencies
  - 31.5.1 I/O Lines
  - 31.5.2 Clocks
- 31.6 Functional Description
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
- 32.9 NVM Characteristics
- 32.10 Oscillators Characteristics
- 32.11 PTC Typical Characteristics
- 32.12 Timing Characteristics
33. Packaging Information
- 33.1 Thermal Considerations
  - 33.1.1 Thermal Resistance Data
  - 33.1.2 Junction Temperature
- 33.2 Package Drawings
- 33.3 Soldering Profile
34. Schematic Checklist
- 34.1 Introduction
- 34.2 Power Supply
  - 34.2.1 Power Supply Connections
- 34.3 External Analog Reference Connections
- 34.4 External Reset Circuit
- 34.5 Unused or Unconnected Pins
- 34.6 Clocks and Crystal Oscillators
- 34.7 Programming and Debug Ports
35. Errata
- 35.1 Revision D
- 35.2 Revision C
- 35.3 Revision B
- 35.4 Revision A
36. Datasheet Revision History
- 36.1 Rev. K – 05/2014
- 36.2 Rev. J – 12/2013
- 36.3 Rev. I – 12/2013
- 36.4 Rev. H – 10/2013
- 36.5 Rev. G – 10/2013
- 36.6 Rev. F – 10/2013
- 36.7 Rev. E – 09/2013
- 36.8 Rev. D – 08/2013
- 36.9 Rev. C – 07/2013
- 36.10 Rev. B – 07/2013
- 36.11 Rev. A – 06/2013
Appendix A. Conventions
- A.1 Numerical Notation
- A.2 Memory Size and Type
- A.3 Frequency and Time
- A.4 Registers and Bits
Appendix B. Acronyms and Abbreviations
Table of Contents

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Atmel | SMART SAM D20 [DATASHEET]

Atmel-42129K–SAM-D20_datasheet–06/2014

15.8.3 CPU Clock Select

Name: CPUSEL

Offset: 0x08

Reset: 0x00

Property: Write-Protected

z Bits 7:3 – Reserved

These bits are unused and reserved for future use. For compatibility with future devices, always write these bits to

zero when this register is written. These bits will always return zero when read.

z Bits 2:0 – CPUDIV[2:0]: CPU Prescaler Selection

These bits define the division ratio of the main clock prescaler (2

Bit76543210

CPUDIV[2:0]

AccessRRRRRR/WR/WR/W

Reset00000000

Table 15-6. CPU Clock Frequency Ratio

CPUDIV[1:0] Description

0x0 Divide by 1

0x1 Divide by 2

0x2 Divide by 4

0x3 Divide by 8

0x4 Divide by 16

0x5 Divide by 32

0x6 Divide by 64

0x7 Divide by 128