ATmega128A Atmel Corporation, ATmega128A Datasheet - Page 12

• Manufacturer Part Number: ATmega128A
• Manufacturer: Atmel Corporation

Specifications of ATmega128A

• Flash (kbytes): 128 Kbytes
• Pin Count: 64
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 53
• Ext Interrupts: 8
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Uart: 2
• 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: No
• Crypto Engine: No
• Sram (kbytes): 4
• 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: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 4
• Output Compare Channels: 8
• Input Capture Channels: 2
• Pwm Channels: 7
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

6.5.1
8151H–AVR–02/11
X-register, Y-register, and Z-register
Figure 6-2 on page 12
CPU.
Figure 6-2.
Most of the instructions operating on the Register file have direct access to all registers, and
most of them are single cycle instructions.
As shown in
directly into the first 32 locations of the user Data Space. Although not being physically imple-
mented as SRAM locations, this memory organization provides great flexibility in access of the
registers, as the X-, Y-, and Z-pointer Registers can be set to index any register in the file.
The registers R26:R31 have some added functions to their general purpose usage. These regis-
ters are 16-bit address pointers for indirect addressing of the Data Space. The three indirect
address registers X, Y, and Z are described in
• One 8-bit output operand and one 8-bit result input
• Two 8-bit output operands and one 8-bit result input
• Two 8-bit output operands and one 16-bit result input
• One 16-bit output operand and one 16-bit result input
Registers
Purpose
Working
General
Figure
Atmel
6-2, each register is also assigned a data memory address, mapping them
®
AVR
shows the structure of the 32 general purpose working registers in the
®
CPU General Purpose Working Registers
7
R13
R14
R15
R16
R17
R26
R27
R28
R29
R30
R31
R0
R1
R2
…
…
Figure
0
6-3.
Addr.
$0D
$0E
$1A
$1B
$1C
$1D
$1E
$00
$01
$02
$0F
$10
$11
$1F
ATmega128A
X-register High Byte
Y-register High Byte
Z-register High Byte
X-register Low Byte
Y-register Low Byte
Z-register Low Byte
12