Atmel Atmel-ICE User Manual

7. Advanced Debugging Techniques
7.1. Atmel AVR UC3 Targets
7.1.1. EVTI / EVTO Usage
The EVTI and EVTO pins are not accessible on the Atmel-ICE. However, they can still be used in
conjunction with other external equipment.
EVTI can be used for the following purposes:
• The target can be forced to stop execution in response to an external event. If the Event In Control
(EIC) bits in the DC register are written to 0b01, high-to-low transition on the EVTI pin will generate
a breakpoint condition. EVTI must remain low for one CPU clock cycle to guarantee that a
breakpoint is triggered. The External Breakpoint bit (EXB) in DS is set when this occurs.
• Generating trace synchronization messages. Not used by the Atmel-ICE.
EVTO can be used for the following purposes:
•
Indicating that the CPU has entered debug mode. Setting the EOS bits in DC to 0b01 causes the
EVTO pin to be pulled low for one CPU clock cycle when the target device enters debug mode.
This signal can be used as a trigger source for an external oscilloscope.
• Indicating that the CPU has reached a breakpoint or watchpoint. By setting the EOC bit in a
corresponding Breakpoint/Watchpoint Control Register, the breakpoint or watchpoint status is
indicated on the EVTO pin. The EOS bits in DC must be set to 0xb10 to enable this feature. The
EVTO pin can then be connected to an external oscilloscope in order to examine watchpoint timing.
• Generating trace timing signals. Not used by the Atmel-ICE.
7.2. debugWIRE Targets
7.2.1. debugWIRE Software Breakpoints
The debugWIRE OCD is drastically scaled down when compared to the Atmel megaAVR (JTAG) OCD.
This means that it does not have any program counter breakpoint comparators available to the user for
debugging purposes. One such comparator does exist for purposes of run-to-cursor and single-stepping
operations, but additional user breakpoints are not supported in hardware.
Instead, the debugger must make use of the AVR BREAK instruction. This instruction can be placed in
FLASH, and when it is loaded for execution it will cause the AVR CPU to enter stopped mode. To support
breakpoints during debugging, the debugger must insert a BREAK instruction into FLASH at the point at
which the users requests a breakpoint. The original instruction must be cached for later replacement.
When single stepping over a BREAK instruction, the debugger has to execute the original cached
instruction in order to preserve program behavior. In extreme cases, the BREAK has to be removed from
FLASH and replaced later. All these scenarios can cause apparent delays when single stepping from
breakpoints, which will be exacerbated when the target clock frequency is very low.
It is thus recommended to observe the following guidelines, where possible:
• Always run the target at as high a frequency as possible during debugging. The debugWIRE
physical interface is clocked from the target clock.
• Try to minimize on the number of breakpoint additions and removals, as each one require a FLASH
page to be replaced on the target
Atmel Atmel-ICE [USER GUIDE]
Atmel-42330C-Atmel-ICE_User Guide-10/2016
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Atmel Atmel-ICE Specifications

General

Brand	Atmel
Model	Atmel-ICE
Category	Microcontrollers
Language	English

Summary

Introduction to Atmel-ICE Features

Atmel-ICE Features Overview

Describes the key features of the Atmel-ICE development tool, including compatibility and supported interfaces.

Getting Started with Atmel-ICE

Atmel-ICE Full Kit Contents

Lists the items included in the Atmel-ICE full kit, essential for initial setup and operation.

Assembling the Atmel-ICE Unit

Provides instructions on how to connect cables and prepare the Atmel-ICE unit for use.

Connecting the Atmel-ICE to Target Devices

Connecting AVR and SAM Target Devices

Explains how to connect the Atmel-ICE to various target microcontroller devices.

Connecting to a JTAG Target

Details the procedure for connecting the Atmel-ICE to target devices using the JTAG interface.

On-chip Debugging Introduction

Introduction to On-chip Debugging

Introduces the concept of on-chip debugging and its role in development.

Atmel-ICE Software Integration

Atmel Studio Integration

Explains how to integrate and use the Atmel-ICE with the Atmel Studio IDE.

Advanced Debugging Techniques

debugWIRE Target Techniques

Covers specific techniques and considerations for debugging with the debugWIRE interface.

Release History and Known Issues

Firmware Release History

Lists past firmware versions and their associated changes and improvements.

Product Compliance Overview

Information regarding the product's compliance with RoHS, WEEE, CE, and FCC regulations.

Introduction to System Requirements

System Requirements for Atmel-ICE

Outlines the necessary software and hardware requirements for using the Atmel-ICE.

Getting Started with Atmel-ICE Kits

Atmel-ICE Kit Overview

Provides a diagrammatic overview of the different Atmel-ICE kit options and their components.

Opening the Atmel-ICE Unit

Details the procedure for safely opening the Atmel-ICE unit.

Connecting Atmel-ICE to Targets

Connecting AVR and SAM Target Devices

Explains how to connect the Atmel-ICE to various target microcontroller devices.

Connecting to a JTAG Target

Details the procedure for connecting the Atmel-ICE to target devices using the JTAG interface.

Connecting to an SWD Target

Explains how to connect the Atmel-ICE to target devices using the SWD interface.

On-chip Debugging for SAM Devices

Introduction to On-chip Debugging

Introduces the concept of on-chip debugging and its role in development.

SAM Devices with JTAG/SWD

Details on-chip debugging for SAM devices using JTAG and SWD interfaces.

ARM CoreSight Components Description

Describes the CoreSight components used in Atmel ARM Cortex-M microcontrollers.

AVR UC3 Debugging with JTAG/aWire

Atmel AVR UC3 On-chip Debug System

Explains the on-chip debug system for Atmel AVR UC3 microcontrollers.

JTAG Physical Interface for AVR UC3

Details the physical JTAG interface for AVR UC3 devices.

tinyAVR, megaAVR, XMEGA Device Interfaces

JTAG Physical Interface for AVR Devices

Describes the JTAG physical interface for tinyAVR, megaAVR, and XMEGA devices.

Connecting to a JTAG Target

Guides on connecting the Atmel-ICE to JTAG targets for these device families.

Connecting to an SPI Target

Explains how to connect the Atmel-ICE to target devices using the SPI interface.

megaAVR Debugging Considerations

Software Breakpoints for megaAVR

Discusses limitations and usage of software breakpoints for megaAVR devices.

JTAG Clock Frequency for megaAVR

Details clock frequency considerations for JTAG debugging of megaAVR devices.

AVR XMEGA Debugging Considerations

OCD and Clocking for XMEGA

Explains OCD clocking behavior for XMEGA devices during stopped mode.

Hardware Breakpoints for XMEGA

Details the hardware breakpoint capabilities and restrictions for XMEGA devices.

debugWIRE Special Considerations

debugWIRE Enable Fuse (DWEN) Management

Details the importance and usage of the DWEN fuse for enabling debugwire functionality.

Atmel-ICE Hardware Description

Atmel-ICE Architecture Overview

Provides a block diagram and explanation of the Atmel-ICE's internal architecture.

Software Integration with Atmel Studio

Atmel Studio Integration Guide

Explains how to integrate and use the Atmel-ICE with the Atmel Studio IDE.

Programming Options Configuration

Details the configuration options for programming Atmel AVR and SAM devices.

Debug Options Configuration

Covers important configuration options for debugging within Atmel Studio.

Advanced Debugging Techniques

Atmel AVR UC3 Target Techniques

Discusses advanced debugging techniques applicable to Atmel AVR UC3 targets.

debugWIRE Target Techniques

Covers specific techniques and considerations for debugging with the debugwire interface.

Release History and Known Issues

Firmware Release History Details

Lists past firmware versions and their associated changes and improvements.

Known Issues with Atmel-ICE

Details known issues and limitations with the Atmel-ICE hardware and firmware.

Product Compliance Information

RoHS and WEEE Compliance

Information regarding the product's compliance with RoHS and WEEE directives.

CE and FCC Compliance

Details the product's compliance with CE and FCC regulations for electromagnetic emissions.

Revision History of Document