ATmega168A Atmel Corporation, ATmega168A Datasheet - Page 70

• Manufacturer Part Number: ATmega168A
• Manufacturer: Atmel Corporation

Specifications of ATmega168A

• Flash (kbytes): 16 Kbytes
• Pin Count: 32
• Max. Operating Frequency: 20 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 23
• Ext Interrupts: 24
• Usb Speed: No
• Usb Interface: No
• Spi: 2
• Twi (i2c): 1
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 1
• Eeprom (bytes): 512
• 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: 3
• Output Compare Channels: 6
• Input Capture Channels: 1
• Pwm Channels: 6
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

12.5
12.5.1
8271D–AVR–05/11
Register Description
Moving Interrupts Between Application and Boot Space, ATmega88A/88PA, ATmega168A/168PA and
ATmega328/328P
When the BOOTRST Fuse is programmed, the Boot section size set to 2Kbytes 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 in ATmega328/328P is:
The MCU Control Register controls the placement of the Interrupt Vector table.
MCUCR – MCU Control Register
Note:
• 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
Self-Programming” on page 280
tables, a special write procedure must be followed to change the IVSEL bit:
Bit
0x35 (0x55)
Read/Write
Initial Value
;
.org 0x3C00
0x3C00
0x3C01
0x3C02
0x3C03
0x3C04
0x3C05
Address Labels Code
;
.org 0x3C00
0x3C00
0x3C02
0x3C04
...
0x3C32
;
0x3C33
0x3C34
0x3C35
0x3C36
0x3C37
0x3C38
1. BODS and BODSE only available for picoPower devices ATmega48PA/88PA/168PA/328P
RESET: ldi
RESET: ldi
R
7
–
0
ATmega48A/PA/88A/PA/168A/PA/328/P
out
ldi
out
sei
<instr>
jmp
jmp
jmp
...
jmp
out
ldi
out
sei
<instr>
BODS
R/W
6
0
(1)
r16,high(RAMEND); Main program start
SPH,r16
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
BODSE
xxx
xxx
for details. To avoid unintentional changes of Interrupt Vector
R/W
5
0
(1)
PUD
R/W
4
0
; Set Stack Pointer to top of RAM
; Enable interrupts
Comments
; Reset handler
; IRQ0 Handler
; IRQ1 Handler
;
; Store Program Memory Ready Handler
; Set Stack Pointer to top of RAM
; Enable interrupts
”Boot Loader Support – Read-While-Write
R
3
–
0
R
2
–
0
IVSEL
R/W
1
0
IVCE
R/W
0
0
MCUCR
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