ATtiny22L

6

Notes:

1. For compatibility with future devices, reserved bits should be written to zero if accessed. Reserved I/O memory addresses

should never be written.

2. Some of the status flags are cleared by writing a logical one to them. Note that the CBI and SBI instructions will operate on

all bits in the I/O register, writing a one back into any flag read as set, thus clearing the flag. The CBI and SBI instructions

work with registers $00 to $1F only.

Register Summary

Address

Name

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

Page

$3F ($5F)

SREG

I

T

H

S

V

N

Z

C

page 16

$3E ($5E)

Reserved

$3D ($5D)

SPL

SP7

SP6

SP5

SP4

SP3

SP2

SP1

SP0

page 17

$3C ($5C)

Reserved

$3B ($5B)

GIMSK

-INT0

-

-

-

-

-

-

page 23

$3A ($5A)

GIFR

-INTF0

page 23

$39 ($59)

TIMSK

-

-

-

-

-

-TOIE0

-

page 23

$38 ($58)

TIFR

-

-

-

-

-

-TOV0

-

page 24

$37 ($57)

Reserved

$36 ($56)

Reserved

$35 ($55)

MCUCR

-

-SE

SM

-

-

ISC01

ISC00

page 24

$34 ($54)

MCUSR

-

-

-

-

-

-

EXTRF

PORF

page 22

$33 ($53)

TCCR0

-

-

-

-

-

CS02

CS01

CS00

page 27

$32 ($52)

TCNT0

Timer/Counter0 (8 Bit)

page 28

$31 ($51)

Reserved

$30 ($50)

Reserved

$2F ($4F)

Reserved

$2E ($4E)

Reserved

$2D ($4D)

Reserved

$2C ($4C)

Reserved

$2B ($4B)

Reserved

$2A ($4A)

Reserved

$29 ($49)

Reserved

$28 ($48)

Reserved

$27 ($47)

Reserved

$26 ($46)

Reserved

$25 ($45)

Reserved

$24 ($44)

Reserved

$23 ($43)

Reserved

$22 ($42)

Reserved

$21 ($41)

WDTCR

-

-

-

WDTOE

WDE

WDP2

WDP1

WDP0

page 28

$20 ($40)

Reserved

$1F ($3F)

Reserved

$1E ($3E)

EEAR

-

EEPROM Address Register

page 30

$1D ($3D)

EEDR

EEPROM Data register

page 30

$1C ($3C)

EECR

-

-

-

-

-

EEMW

EEWE

EERE

page 30

$1B ($3B)

Reserved

$1A ($3A)

Reserved

$19 ($39)

Reserved

$18 ($38)

PORTB

-

-

-

PORTB

PORTB

PORTB

PORTB

PORTB

page 32

$17 ($37)

DDRB

-

-

-

DDB4

DDB3

DDB2

DDB1

DDB0

page 32

$16 ($36)

PINB

-

-

-

PINB4

PINB3

PINB2

PINB1

PINB0

page 32

$15 ($35)

Reserved

…

Reserved

$00 ($20)

Reserved