ATmega640 Atmel Corporation, ATmega640 Datasheet - Page 110

• Manufacturer Part Number: ATmega640
• Manufacturer: Atmel Corporation

Specifications of ATmega640

• Flash (kbytes): 64 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

14.4
14.4.1
2549N–AVR–05/11
Register Description
MCUCR – MCU Control Register
• Bit 1 – IVSEL: Interrupt Vector Select
When the IVSEL bit is cleared (zero), the Interrupt Vectors are placed at the start of the Flash
memory. When this bit is set (one), the Interrupt Vectors are moved to the beginning of the Boot
Loader section of the Flash. The actual address of the start of the Boot Flash Section is deter-
mined by the BOOTSZ Fuses. Refer to the section
details. To avoid unintentional changes of Interrupt Vector tables, a special write procedure must
be followed to change the IVSEL bit (see
tion” on page
Bit
0x35 (0x55)
Read/Write
Initial Value
Assembly Code Example
C Code Example
1. Write the Interrupt Vector Change Enable (IVCE) bit to one.
2. Within four cycles, write the desired value to IVSEL while writing a zero to IVCE.
Move_interrupts:
void Move_interrupts(void)
{
uchar temp;
}
; Get MCUCR
in
mov r17, r16
; Enable change of Interrupt Vectors
ori r16, (1<<IVCE)
out MCUCR, r16
; Move interrupts to Boot Flash section
ori r16, (1<<IVSEL)
out MCUCR, r17
ret
/* Get MCUCR*/
temp = MCUCR;
/* Enable change of Interrupt Vectors */
MCUCR = temp|(1<<IVCE);
/* Move interrupts to Boot Flash section */
MCUCR = temp|(1<<IVSEL);
r16, MCUCR
109):
JTD
R/W
7
0
6
–
R
0
ATmega640/1280/1281/2560/2561
R
5
–
0
PUD
R/W
4
0
“Moving Interrupts Between Application and Boot Sec-
R
3
–
0
“Memory Programming” on page 335
R
2
–
0
IVSEL
R/W
1
0
IVCE
R/W
0
0
MCUCR
110
for