ATtiny13A Atmel Corporation, ATtiny13A Datasheet - Page 11

• Manufacturer Part Number: ATtiny13A
• Manufacturer: Atmel Corporation

Specifications of ATtiny13A

• Flash (kbytes): 1 Kbytes
• Pin Count: 8
• Max. Operating Frequency: 20 MHz
• Cpu: 8-bit AVR
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 6
• Ext Interrupts: 6
• Usb Speed: No
• Usb Interface: No
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 4
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 0.06
• Eeprom (bytes): 64
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: Yes
• Temp. Range (deg C): -40 to 125
• I/o Supply Class: 1.8 to 5.5
• Operating Voltage (vcc): 1.8 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 1
• Output Compare Channels: 2
• Pwm Channels: 2
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

4.5
4.5.1
8126E–AVR–07/10
Stack Pointer
SPL – Stack Pointer Low
Figure 4-3.
In the different addressing modes these address registers have functions as fixed displacement,
automatic increment, and automatic decrement (see the instruction set reference for details).
The Stack is mainly used for storing temporary data, for storing local variables and for storing
return addresses after interrupts and subroutine calls. The Stack Pointer Register always points
to the top of the Stack. Note that the Stack is implemented as growing from higher memory loca-
tions to lower memory locations. This implies that a Stack PUSH command decreases the Stack
Pointer.
The Stack Pointer points to the data SRAM Stack area where the Subroutine and Interrupt
Stacks are located. This Stack space in the data SRAM is automaticall defined to the last
address in SRAM during power on reset. The Stack Pointer must be set to point above 0x60.
The Stack Pointer is decremented by one when data is pushed onto the Stack with the PUSH
instruction, and it is decremented by two when the return address is pushed onto the Stack with
subroutine call or interrupt. The Stack Pointer is incremented by one when data is popped from
the Stack with the POP instruction, and it is incremented by two when data is popped from the
Stack with return from subroutine RET or return from interrupt RETI.
The AVR Stack Pointer is implemented as two 8-bit registers in the I/O space. The number of
bits actually used is implementation dependent. Note that the data space in some implementa-
tions of the AVR architecture is so small that only SPL is needed. In this case, the SPH Register
will not be present.
X-register
Y-register
Z-register
Bit
0x3D
Read/Write
Initial Value
The X-, Y-, and Z-registers
R/W
SP7
7
1
15
7
R29 (0x1D)
15
7
R31 (0x1F)
15
7
R27 (0x1B)
SP6
R/W
6
0
SP5
R/W
5
0
YH
ZH
0
XH
SP4
R/W
4
1
SP3
R/W
3
1
0
0
7
R28 (0x1C)
7
R30 (0x1E)
7
R26 (0x1A)
SP2
R/W
2
1
SP1
R/W
1
1
YL
ZL
XL
0
SP0
R/W
0
1
SPL
11
0
0
0
0
0