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

24.5.9 Analog Connections

Not applicable.

24.6 Functional Description

24.6.1 Principle of Operation

The USART uses three communication lines for data transfer:

z RxD for receiving

z TxD for transmitting

z XCK for the transmission clock in synchronous operation

USART data transfer is frame based, where a serial frame consists of:

z 1 start bit

z 5, 6, 7, 8 or 9 data bits

z MSB or LSB first

z No, even or odd parity bit

z 1 or 2 stop bits

A frame starts with the start bit followed by one character of data bits. If enabled, the parity bit is inserted after the data

bits and before the first stop bit. One frame can be directly followed by a new frame, or the communication line can return

to the idle (high) state. Figure 24-2 illustrates the possible frame formats. Bits inside brackets are optional.

Figure 24-2. Frame Formats

St Start bit; always low

(n) Data bits; 0 to 8

P Parity bit; odd or even

Sp Stop bit; always high

IDLE No transfers on the communication line; always high in this state

24.6.2 Basic Operation

24.6.2.1 Initialization

The following registers are enable-protected, meaning they can only be written when the USART is disabled

(CTRLA.ENABLE is zero):

z Control A register (CTRLA), except the Enable (ENABLE) and Software Reset (SWRST) bits

z Control B register (CTRLB), except the Receiver Enable (RXEN) and Transmitter Enable (TXEN) bits

z Baud register (BAUD)

Any writes to these registers when the USART is enabled or is being enabled (CTRLA.ENABLE is one) will be discarded.

Writes to these registers) while the peripheral is being disabled will be completed after the disabling is complete.

Before the USART is enabled, it must be configured, as outlined in the following steps:

z USART mode with external or internal clock must be selected first by writing 0x0 or 0x1 to the Operating Mode bit

group in the Control A register (CTRLA.MODE)

1 2 3 4 [5] [6] [7] [8]0St(IDLE) Sp1 [Sp2] (St/IDLE)[P]

Frame