ATMEGA644V-10MU Atmel, ATMEGA644V-10MU Datasheet - Page 58

• Manufacturer Part Number: ATMEGA644V-10MU
• Description: IC AVR MCU FLASH 64K 44-QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA644V-10MU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 10MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 32
• Program Memory Size: 64KB (32K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 2K x 8
• Ram Size: 4K 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: 44-VQFN Exposed Pad
• Package: 44QFN EP
• Device Core: AVR
• Family Name: ATmega
• Maximum Speed: 10 MHz
• Operating Supply Voltage: 2.5|3.3|5 V
• Data Bus Width: 8 Bit
• Number Of Programmable I/os: 32
• Interface Type: JTAG/SPI/TWI/USART
• On-chip Adc: 8-chx10-bit
• Number Of Timers: 3
• Processor Series: ATMEGA64x
• Core: AVR8
• Data Ram Size: 4 KB
• Maximum Clock Frequency: 20 MHz
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• For Use With: ATSTK600-TQFP44 - STK600 SOCKET/ADAPTER 44-TQFPATSTK600 - DEV KIT FOR AVR/AVR32770-1007 - ISP 4PORT ATMEL AVR MCU SPI/JTAGATAVRISP2 - PROGRAMMER AVR IN SYSTEM
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

10.1.1
10.2
10.2.1
58
Register Description
ATmega644
Moving Interrupts Between Application and Boot Space
MCUCR – MCU Control Register
When the BOOTRST Fuse is programmed, the Boot section size set to 8 Kbytes and the IVSEL
bit in the MCUCR Register is set before any interrupts are enabled, the most typical and general
program setup for the Reset and Interrupt Vector Addresses is:
The General Interrupt Control Register controls the placement of the Interrupt Vector table.
• 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:
Interrupts will automatically be disabled while this sequence is executed. Interrupts are disabled
in the cycle IVCE is set, and they remain disabled until after the instruction following the write to
Bit
0x35 (0x55)
Read/Write
Initial Value
0x1F002
0x1F003
0x1F004
0x1F005
Address Labels Code
;
.org 0x1F000
0x1F000
0x1F002
0x1F004
...
0x1F036
;
0x1F03E RESET: ldi
0x1F03F
0x1F040
0x1F041
0x1F042
0x1FO43
a. Write the Interrupt Vector Change Enable (IVCE) bit to one.
b. Within four cycles, write the desired value to IVSEL while writing a zero to IVCE.
R/W
JTD
7
0
ldi
out
sei
<instr>
jmp
jmp
jmp
...
jmp
out
ldi
out
sei
<instr>
R
6
–
0
r16,low(RAMEND)
SPL,r16
RESET
EXT_INT0
EXT_INT1
...
SPM_RDY
r16,high(RAMEND); Main program start
SPH,r16
r16,low(RAMEND)
SPL,r16
xxx
xxx
R
5
–
0
PUD
R/W
4
0
; Enable interrupts
Comments
; Reset handler
; IRQ0 Handler
; IRQ1 Handler
;
; SPM Ready Handler
; Set Stack Pointer to top of RAM
; Enable interrupts
”Memory Programming” on page 284
R
3
–
0
R
2
–
0
IVSEL
R/W
1
0
IVCE
R/W
0
0
2593N–AVR–07/10
MCUCR
for