A000047 Arduino, A000047 Datasheet - Page 308

• Manufacturer Part Number: A000047
• Description: MCU, MPU & DSP Development Tools Mega2560
• Manufacturer: Arduino
• Series: -r
• Type: MCUr

Specifications of A000047

• Processor To Be Evaluated: ATmega2560
• Interface Type: USB, I2C, SPI
• Dimensions: 4 in x 2.1 in
• Operating Supply Voltage: 5 V
• Contents: Board
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: ATmega2560

27.6
27.6.1
27.6.2
27.7
27.8
2549M–AVR–09/10
Boundary-scan Related Register in I/O Memory
ATmega640/1280/1281/2560/2561 Boundary-scan Order
Boundary-scan Description Language Files
MCUCR – MCU Control Register
MCUSR – MCU Status Register
The MCU Control Register contains control bits for general MCU functions.
• Bits 7 – JTD: JTAG Interface Disable
When this bit is zero, the JTAG interface is enabled if the JTAGEN Fuse is programmed. If this
bit is one, the JTAG interface is disabled. In order to avoid unintentional disabling or enabling of
the JTAG interface, a timed sequence must be followed when changing this bit: The application
software must write this bit to the desired value twice within four cycles to change its value. Note
that this bit must not be altered when using the On-chip Debug system.
The MCU Status Register provides information on which reset source caused an MCU reset.
• Bit 4 – JTRF: JTAG Reset Flag
This bit is set if a reset is being caused by a logic one in the JTAG Reset Register selected by
the JTAG instruction AVR_RESET. This bit is reset by a Power-on Reset, or by writing a logic
zero to the flag.
Table 27-1 on page 309
chain is selected as data path. Bit 0 is the LSB; the first bit scanned in, and the first bit scanned
out. The scan order follows the pin-out order as far as possible. Therefore, the bits of Port A and
Port K is scanned in the opposite bit order of the other ports. Exceptions from the rules are the
Scan chains for the analog circuits, which constitute the most significant bits of the scan chain
regardless of which physical pin they are connected to. In
corresponds to FF0, PXn. Control corresponds to FF1, PXn. Bit 4, bit 5, bit 6 and bit 7 of Port F
is not in the scan chain, since these pins constitute the TAP pins when the JTAG is enabled.
Boundary-scan Description Language (BSDL) files describe Boundary-scan capable devices in
a standard format used by automated test-generation software. The order and function of bits in
the Boundary-scan Data Register are included in this description. BSDL files are available for
ATmega1281/2561 and ATmega640/1280/2560.
Bit
0x35 (0x55)
Read/Write
Initial Value
Bit
0x34 (0x54)
Read/Write
Initial Value
R/W
JTD
7
0
7
–
R
0
shows the Scan order between TDI and TDO when the Boundary-scan
R
R
6
–
0
6
–
0
ATmega640/1280/1281/2560/2561
R
R
5
–
0
5
–
0
JTRF
PUD
R/W
R/W
4
0
4
WDRF
R/W
R
3
–
0
3
See Bit Description
Figure 27-3 on page
BORF
R/W
R
2
–
0
2
EXTRF
IVSEL
R/W
R/W
1
0
1
PORF
IVCE
306, PXn. Data
R/W
R/W
0
0
0
MCUCR
MCUSR
308