ATMEGA8U2-MU Atmel, ATMEGA8U2-MU Datasheet - Page 245

• Manufacturer Part Number: ATMEGA8U2-MU
• Description: MCU AVR 8K FLASH USB 32-VQFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA8U2-MU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: SPI, UART/USART, USB
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 22
• Program Memory Size: 8KB (4K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 32-VQFN Exposed Pad, 32-HVQFN, 32-SQFN, 32-DHVQFN
• Processor Series: ATMEGA8x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 1 KB
• Interface Type: SPI, UART
• Maximum Clock Frequency: 16 MHz
• Number Of Programmable I/os: 22
• Number Of Timers: 2
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT, AT90USBKEY, ATEVK525
• Minimum Operating Temperature: - 40 C
• Package: 32QFN EP
• Device Core: AVR
• Family Name: ATmega
• Maximum Speed: 16 MHz
• Operating Supply Voltage: 3.3|5 V
• For Use With: ATSTK600 - DEV KIT FOR AVR/AVR32ATSTK500 - PROGRAMMER AVR STARTER KIT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Data Converters: -
• Lead Free Status / Rohs Status: Details

24.4
24.5
24.6
24.6.1
7799D–AVR–11/10
Software Break Points
Limitations of debugWIRE
Register Description
DWDR – debugWire Data Register
When designing a system where debugWIRE will be used, the following observations must be
made for correct operation:
Note:
debugWIRE supports Program memory Break Points by the AVR Break instruction. Setting a
Break Point in AVR Studio
tion replaced by the BREAK instruction will be stored. When program execution is continued, the
stored instruction will be executed before continuing from the Program memory. A break can be
inserted manually by putting the BREAK instruction in the program.
The Flash must be re-programmed each time a Break Point is changed. This is automatically
handled by AVR Studio through the debugWIRE interface. The use of Break Points will therefore
reduce the Flash Data retention. Devices used for debugging purposes should not be shipped to
end customers.
The debugWIRE communication pin (dW) is physically located on the same pin as External
Reset (RESET). An External Reset source is therefore not supported when the debugWIRE is
enabled.
The debugWIRE system accurately emulates all I/O functions when running at full speed, i.e.,
when the program in the CPU is running. When the CPU is stopped, care must be taken while
accessing some of the I/O Registers via the debugger (AVR Studio).
A programmed DWEN Fuse enables some parts of the clock system to be running in all sleep
modes. This will increase the power consumption while in sleep. Thus, the DWEN Fuse should
be disabled when debugWire is not used.
The DWDR Register provides a communication channel from the running program in the MCU
to the debugger. This register is only accessible by the debugWIRE and can therefore not be
used as a general purpose register in the normal operations.
Bit
0x31 (0x51)
Read/Write
Initial Value
• Connecting the RESET pin directly to V
• Any capacitors (or additionnal circuitry) connected to the RESET pin must be disconnected
• All external reset sources must be disconnected.
when using debugWire.
some releases of JTAG Ice mkII firmware may require a pull-up resistor with a value between 8
and 14 kOhms when operating at 5V.
R/W
7
0
R/W
®
6
0
will insert a BREAK instruction in the Program memory. The instruc-
R/W
5
0
CC
R/W
4
0
DWDR[7:0]
will not work.
ATmega8U2/16U2/32U2
R/W
3
0
R/W
2
0
R/W
1
0
R/W
0
0
DWDR
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