TINY12 ATMEL [ATMEL Corporation], TINY12 Datasheet - Page 14

• Manufacturer Part Number: TINY12
• Description: 8-bit AVR Microcontroller with 1K Byte Flash
• Manufacturer: ATMEL [ATMEL Corporation]

I/O Memory
Status Register – SREG
14
ATtiny11/12
The I/O space definition of the ATtiny11/12 is shown in the following table:
Table 4. ATtiny11/12 I/O Space
Note:
All the different ATtiny11/12 I/O and peripherals are placed in the I/O space. The differ-
ent I/O locations are accessed by the IN and OUT instructions transferring data between
the 32 general-purpose working registers and the I/O space. I/O registers within the
address range $00 - $1F are directly bit-accessible using the SBI and CBI instructions.
In these registers, the value of single bits can be checked by using the SBIS and SBIC
instructions. Refer to the Instruction Set Summary for more details.
For compatibility with future devices, reserved bits should be written to zero if accessed.
Reserved I/O memory addressed should never be written.
The different I/O and peripherals control registers are explained in the following
sections.
The AVR status register (SREG) at I/O space location $3F is defined as:
• Bit 7 - I: Global Interrupt Enable
The global interrupt enable bit must be set (one) for the interrupts to be enabled. The
individual interrupt enable control is then performed in separate control registers. If the
Bit
$3F
Read/Write
Initial Value
Address Hex
$3B
$3A
$1E
$1D
$1C
$3F
$39
$38
$35
$34
$33
$32
$31
$21
$18
$17
$16
$08
Reserved and unused locations are not shown in the table.
R/W
7
0
I
Name
SREG
GIMSK
GIFR
TIMSK
TIFR
MCUCR
MCUSR
TCCR0
TCNT0
OSCCAL
WDTCR
EEAR
EEDR
EECR
PORTB
DDRB
PINB
ACSR
R/W
6
T
0
Device
ATtiny11/12
ATtiny11/12
ATtiny11/12
ATtiny11/12
ATtiny11/12
ATtiny11/12
ATtiny11/12
ATtiny11/12
ATtiny11/12
ATtiny12
ATtiny11/12
ATtiny12
ATtiny12
ATtiny12
ATtiny11/12
ATtiny11/12
ATtiny11/12
ATtiny11/12
R/W
H
5
0
R/W
S
4
0
Function
Status Register
General Interrupt Mask Register
General Interrupt Flag Register
Timer/Counter Interrupt Mask Register
Timer/Counter Interrupt Flag Register
MCU Control Register
MCU Status Register
Timer/Counter0 Control Register
Timer/Counter0 (8-bit)
Oscillator Calibration Register
Watchdog Timer Control Register
EEPROM Address Register
EEPROM Data Register
EEPROM Control Register
Data Register, Port B
Data Direction Register, Port B
Input Pins, Port B
Analog Comparator Control and Status Register
R/W
V
3
0
R/W
N
2
0
R/W
Z
1
0
R/W
1006D–AVR–07/03
0
C
0
SREG