at90pwm81-16se ATMEL Corporation, at90pwm81-16se Datasheet - Page 231

• Manufacturer Part Number: at90pwm81-16se
• Description: 8-bit Avr Microcontroller With 8k Bytes In- System Programmable Flash
• Manufacturer: ATMEL Corporation

20. debugWIRE On-chip Debug System
20.1
20.2
20.3
7734M–AVR–03/10
Features
Overview
Physical Interface
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The debugWIRE On-chip debug system uses a One-wire, bi-directional interface to control the program
flow, execute AVR instructions in the CPU and to program the different non-volatile memories.
When the debugWIRE Enable (DWEN) Fuse is programmed and Lock bits are unprogrammed, the
debugWIRE system within the target device is activated. The RESET port pin is configured as a wire-
AND (open-drain) bi-directional I/O pin with pull-up enabled and becomes the communication gateway
between target and emulator.
Figure 20-1.
Figure 20-1
The system clock is not affected by debugWIRE and will always be the clock source selected by the
CKSEL Fuses.
When designing a system where debugWIRE will be used, the following observations must be made for
correct operation:
Complete Program Flow Control
Emulates All On-chip Functions, Both Digital and Analog, except RESET Pin
Real-time Operation
Symbolic Debugging Support (Both at C and Assembler Source Level, or for Other HLLs)
Unlimited Number of Program Break Points (Using Software Break Points)
Non-intrusive Operation
Electrical Characteristics Identical to Real Device
Automatic Configuration System
High-Speed Operation
Programming of Non-volatile Memories
shows the schematic of a target MCU, with debugWIRE enabled, and the emulator connector.
The debugWIRE Setup
dW
GND
dW(RESET)
VCC
1.8 - 5.5V
AT90PWM81
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