ATMEGA64A-MNR Atmel, ATMEGA64A-MNR Datasheet - Page 258

• Manufacturer Part Number: ATMEGA64A-MNR
• Description: IC MCU AVR 64K FLASH 8QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA64A-MNR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 53
• Program Memory Size: 64KB (32K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 2K 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: *
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 2 KB
• Interface Type: SPI, UART, I2C
• Maximum Clock Frequency: 16 MHz
• Number Of Programmable I/os: 53
• Operating Supply Voltage: 2.7 V to 5.5 V
• Maximum Operating Temperature: + 105 C
• Mounting Style: SMD/SMT
• Operating Temperature Range: - 40 C to + 85 C
• Processor To Be Evaluated: ATMEGA64A
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

24.8
24.9
24.9.1
24.10 Bibliography
8160C–AVR–07/09
Using the JTAG Programming Capabilities
On-chip Debug Related Register in I/O Memory
OCDR – On-chip Debug Register
Programming of AVR parts via JTAG is performed via the 4-pin JTAG port, TCK, TMS, TDI, and
TDO. These are the only pins that need to be controlled/observed to perform JTAG program-
ming (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 MCUSR 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
The OCDR Register provides a communication channel from the running program in the micro-
controller to the debugger. The CPU can transfer a byte to the debugger by writing to this
location. At the same time, an internal flag; I/O Debug Register Dirty – IDRD – is set to indicate
to the debugger that the register has been written. When the CPU reads the OCDR Register the
7 LSB will be from the OCDR Register, while the MSB is the IDRD bit. The debugger clears the
IDRD bit when it has read the information.
In some AVR devices, this register is shared with a standard I/O location. In this case, the OCDR
Register can only be accessed if the OCDEN Fuse is programmed, and the debugger enables
access to the OCDR Register. In all other cases, the standard I/O location is accessed.
Refer to the debugger documentation for further information on how to use this register.
For more information about general Boundary-scan, the following literature can be consulted:
Bit
0x22 (0x42)
Read/Write
Initial Value
• 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,
Architecture, IEEE, 1993.
1992.
MSB/IDRD
R/W
7
0
R/W
6
0
R/W
“Programming Via the JTAG Interface” on page
5
0
R/W
4
0
R/W
3
0
R/W
2
0
R/W
ATmega64A
1
0
LSB
R/W
0
0
314.
OCDR
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