ATmega1280 Atmel Corporation, ATmega1280 Datasheet - Page 305

• Manufacturer Part Number: ATmega1280
• Manufacturer: Atmel Corporation

Specifications of ATmega1280

• Flash (kbytes): 128 Kbytes
• Pin Count: 100
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 86
• Ext Interrupts: 32
• Usb Speed: No
• Usb Interface: No
• Spi: 5
• Twi (i2c): 1
• Uart: 4
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 16
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 8
• Eeprom (bytes): 4096
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8 to 5.5
• Operating Voltage (vcc): 1.8 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 6
• Output Compare Channels: 16
• Input Capture Channels: 4
• Pwm Channels: 15
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

28.4.3
28.4.4
28.4.5
28.5
28.5.1
2549N–AVR–05/11
Boundary-scan Chain
SAMPLE_PRELOAD; 0x2
AVR_RESET; 0xC
BYPASS; 0xF
Scanning the Digital Port Pins
The active states are:
•
•
Mandatory JTAG instruction for pre-loading the output latches and taking a snap-shot of the
input/output pins without affecting the system operation. However, the output latches are not
connected to the pins. The Boundary-scan Chain is selected as Data Register.
The active states are:
•
•
•
The AVR specific public JTAG instruction for forcing the AVR device into the Reset mode or
releasing the JTAG reset source. The TAP controller is not reset by this instruction. The one bit
Reset Register is selected as Data Register. Note that the reset will be active as long as there is
a logic “one” in the Reset Chain. The output from this chain is not latched.
The active states are:
•
Mandatory JTAG instruction selecting the Bypass Register for Data Register.
The active states are:
•
•
The Boundary-scan chain has the capability of driving and observing the logic levels on the digi-
tal I/O pins, as well as the boundary between digital and analog logic for analog circuitry having
off-chip connection.
Figure 28-3 on page 306
function is disabled during Boundary-scan when the JTAG IC contains EXTEST or
SAMPLE_PRELOAD. The cell consists of a bi-directional pin cell that combines the three sig-
nals Output Control - OCxn, Output Data - ODxn, and Input Data - IDxn, into only a two-stage
Shift Register. The port and pin indexes are not used in the following description.
The Boundary-scan logic is not included in the figures in the datasheet.
shows a simple digital port pin as described in the section
ary-scan details from
307.
When no alternate port function is present, the Input Data - ID - corresponds to the PINxn Regis-
ter value (but ID has no synchronizer), Output Data corresponds to the PORT Register, Output
Capture-DR: Data in the IDCODE Register is sampled into the Boundary-scan Chain
Shift-DR: The IDCODE scan chain is shifted by the TCK input
Capture-DR: Data on the external pins are sampled into the Boundary-scan Chain
Shift-DR: The Boundary-scan Chain is shifted by the TCK input
Update-DR: Data from the Boundary-scan chain is applied to the output latches. However,
the output latches are not connected to the pins
Shift-DR: The Reset Register is shifted by the TCK input
Capture-DR: Loads a logic “0” into the Bypass Register
Shift-DR: The Bypass Register cell between TDI and TDO is shifted
Figure 28-3 on page 306
shows the Boundary-scan Cell for a bi-directional port pin. The pull-up
ATmega640/1280/1281/2560/2561
replaces the dashed box in
“I/O-Ports” on page
Figure 28-4 on page 307
Figure 28-4 on page
70. The Bound-
305