ATMEGA325A-MU Atmel, ATMEGA325A-MU Datasheet - Page 238
![IC MCU AVR 32K FLASH 64VQFN](/photos/12/13/121326/313-64-qfn_sml.jpg)
ATMEGA325A-MU
Manufacturer Part Number
ATMEGA325A-MU
Description
IC MCU AVR 32K FLASH 64VQFN
Manufacturer
Atmel
Series
AVR® ATmegar
Specifications of ATMEGA325A-MU
Core Processor
AVR
Core Size
8-Bit
Speed
20MHz
Connectivity
SPI, UART/USART, USI
Peripherals
Brown-out Detect/Reset, POR, PWM, WDT
Number Of I /o
54
Program Memory Size
32KB (16K x 16)
Program Memory Type
FLASH
Eeprom Size
1K x 8
Ram Size
2K x 8
Voltage - Supply (vcc/vdd)
1.8 V ~ 5.5 V
Data Converters
A/D 8x10b
Oscillator Type
Internal
Operating Temperature
-40°C ~ 85°C
Package / Case
64-VFQFN Exposed Pad
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
- Current page: 238 of 680
- Download datasheet (37Mb)
23.9
23.9.1
23.10 Bibliography
238
On-chip Debug Related Register in I/O Memory
ATmega165A/165PA/325A/325PA/3250A/3250PA/645A/645P/645
OCDR – On-chip Debug Register
The JTAG programming capability supports:
• Flash programming and verifying.
• EEPROM programming and verifying.
• Fuse programming and verifying.
• Lock bit programming and verifying.
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:
• 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, 1992.
Bit
0x31 (0x51)
Read/Write
Initial Value
Architecture, IEEE, 1993.
MSB/IDRD
R/W
7
0
R/W
6
0
”Programming via the JTAG Interface” on page
R/W
5
0
R/W
4
0
R/W
3
0
R/W
2
0
R/W
1
0
LSB
R/W
0
0
8285B–AVR–03/11
304.
OCDR
Related parts for ATMEGA325A-MU
Image
Part Number
Description
Manufacturer
Datasheet
Request
R
![ATmega32](/images/manufacturer_photos/0/0/79/atmel_corporation_tmb.jpg)
Part Number:
Description:
Manufacturer:
Atmel Corporation
Datasheet:
![ATMEGA32-8AU](/images/manufacturer_photos/0/0/79/atmel_corporation_tmb.jpg)
Part Number:
Description:
Manufacturer:
ATMEL Corporation
Datasheet:
![ATMEGA32-16MU](/photos/12/13/121316/313-44-qfn_tmb.jpg)
Part Number:
Description:
IC AVR MCU 32K 16MHZ 5V 44-QFN
Manufacturer:
Atmel
Datasheet:
![ATMEGA32-16PU](/photos/6/70/67049/453-40-dip_tmb.jpg)
Part Number:
Description:
IC AVR MCU 32K 16MHZ 5V 40DIP
Manufacturer:
Atmel
Datasheet:
![ATMEGA32-16AU](/photos/6/70/67042/313-44-tqfp_tmb.jpg)
Part Number:
Description:
IC AVR MCU 32K 16MHZ 5V 44TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA32-16PI](/photos/6/70/67049/453-40-dip_tmb.jpg)
Part Number:
Description:
IC AVR MCU 32K 16MHZ IND 40-DIP
Manufacturer:
Atmel
Datasheet:
![ATMEGA32-16AI](/photos/6/70/67042/313-44-tqfp_tmb.jpg)
Part Number:
Description:
IC AVR MCU 32K 16MHZ IND 44-TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA32-16AUR](/images/manufacturer_photos/0/0/78/atmel_tmb.jpg)
Part Number:
Description:
MCU AVR 32KB FLASH 16MHZ 44TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA32-16MUR](/images/manufacturer_photos/0/0/78/atmel_tmb.jpg)
Part Number:
Description:
MCU AVR 32KB FLASH 16MHZ 44QFN
Manufacturer:
Atmel
Datasheet:
![ATMEGA32-16AQ](/photos/6/70/67042/313-44-tqfp_tmb.jpg)
Part Number:
Description:
MCU AVR 32K FLASH 16MHZ 44-TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA32-16PC](/photos/6/70/67049/453-40-dip_tmb.jpg)
Part Number:
Description:
IC AVR MCU 32K 16MHZ COM 40-DIP
Manufacturer:
Atmel
Datasheet:
![ATMEGA32-16MC](/photos/12/13/121316/313-44-qfn_tmb.jpg)
Part Number:
Description:
IC AVR MCU 32K 16MHZ COM 44-QFN
Manufacturer:
Atmel
Datasheet:
![ATMEGA32-16AC](/photos/6/70/67042/313-44-tqfp_tmb.jpg)
Part Number:
Description:
IC AVR MCU 32K 16MHZ COM 44-TQFP
Manufacturer:
Atmel
Datasheet: