ATMEGA128A-AUR Atmel, ATMEGA128A-AUR Datasheet - Page 255

• Manufacturer Part Number: ATMEGA128A-AUR
• Description: MCU AVR 128K FLASH 16MHZ 64TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA128A-AUR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: EBI/EMI, I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 53
• Program Memory Size: 128KB (64K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 4K x 8
• Ram Size: 4K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

24.8
24.9
24.10 IEEE 1149.1 (JTAG) Boundary-scan
24.10.1
24.10.2
8151H–AVR–02/11
Using the JTAG Programming Capabilities
Bibliography
Features
System Overview
Programming of AVR parts via JTAG is performed via the four-pin JTAG port, TCK, TMS, TDI,
and TDO. These are the only pins that need to be controlled/observed to perform JTAG pro-
gramming (in addition to power pins). It is not required to apply 12V externally. The JTAGEN
fuse must be programmed and the JTD bit in the MCUCSR Register must be cleared to enable
the JTAG Test Access Port.
The JTAG programming capability supports:
The Lock bit security is exactly as in Parallel Programming mode. If the Lock bits LB1 or LB2 are
programmed, the OCDEN Fuse cannot be programmed unless first doing a chip erase. This is a
security feature that ensures no back-door exists for reading out the content of a secured
device.
The details on programming through the JTAG interface and programming specific JTAG
instructions are given in the section
For more information about general Boundary-scan, the following literature can be consulted:
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The Boundary-scan Chain has the capability of driving and observing the logic levels on the dig-
ital I/O pins, as well as the boundary between digital and analog logic for analog circuitry having
off-chip connections. At system level, all ICs having JTAG capabilities are connected serially by
the TDI/TDO signals to form a long Shift Register. An external controller sets up the devices to
drive values at their output pins, and observe the input values received from other devices. The
controller compares the received data with the expected result. In this way, Boundary-scan pro-
vides a mechanism for testing interconnections and integrity of components on Printed Circuits
Boards by using the four TAP signals only.
The four IEEE 1149.1 defined mandatory JTAG instructions IDCODE, BYPASS, SAMPLE/PRE-
LOAD, and EXTEST, as well as the AVR specific public JTAG instruction AVR_RESET can be
used for testing the Printed Circuit Board. Initial scanning of the data register path will show the
• Flash programming and verifying
• EEPROM programming and verifying
• Fuse programming and verifying
• Lock bit programming and verifying
• IEEE: IEEE Std 1149.1-1990. IEEE Standard Test Access Port and Boundary-scan
• Colin Maunder: The Board Designers Guide to Testable Logic Circuits, Addison-Wesley,
JTAG (IEEE std. 1149.1 Compliant) Interface
Boundary-scan Capabilities According to the JTAG Standard
Full Scan of all Port Functions as well as Analog Circuitry having Off-chip Connections
Supports the Optional IDCODE Instruction
Additional Public AVR_RESET Instruction to Reset the AVR
Architecture, IEEE, 1993
1992
“Programming Via the JTAG Interface” on page
ATmega128A
308.
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