ATmega1280 Atmel Corporation, ATmega1280 Datasheet - Page 113

• 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

15.2
15.2.1
2549N–AVR–05/11
Register Description
EICRA – External Interrupt Control Register A
Figure 15-1. Normal pin change interrupt.
The External Interrupt Control Register A contains control bits for interrupt sense control.
• Bits 7:0 – ISC31, ISC30 – ISC00, ISC00: External Interrupt 3 - 0 Sense Control Bits
The External Interrupts 3 - 0 are activated by the external pins INT3:0 if the SREG I-flag and the
corresponding interrupt mask in the EIMSK is set. The level and edges on the external pins that
activate the interrupts are defined in
asynchronously. Pulses on INT3:0 pins wider than the minimum pulse width given in
on page 114
rupt. If low level interrupt is selected, the low level must be held until the completion of the
currently executing instruction to generate an interrupt. If enabled, a level triggered interrupt will
generate an interrupt request as long as the pin is held low. When changing the ISCn bit, an
interrupt can occur. Therefore, it is recommended to first disable INTn by clearing its Interrupt
Enable bit in the EIMSK Register. Then, the ISCn bit can be changed. Finally, the INTn interrupt
flag should be cleared by writing a logical one to its Interrupt Flag bit (INTFn) in the EIFR Regis-
ter before the interrupt is re-enabled.
PCINT(0)
Bit
(0x69)
Read/Write
Initial Value
pcint_setflag
pcint_in_(n)
clk
PCINT(n)
pcint_syn
pin_sync
pin_lat
PCIF
will generate an interrupt. Shorter pulses are not guaranteed to generate an inter-
LE
clk
ISC31
R/W
7
0
pin_lat
D
Q
ISC30
R/W
pin_sync
PCINT(0) in PCMSK(x)
6
0
ATmega640/1280/1281/2560/2561
ISC21
pcint_in_(0)
R/W
5
0
Table 15-1 on page
ISC20
R/W
4
0
0
x
clk
ISC11
R/W
3
0
114. Edges on INT3:0 are registered
pcint_syn
ISC10
R/W
2
0
ISC01
pcint_setflag
R/W
1
0
ISC00
R/W
0
0
PCIF
Table 15-2
EICRA
113