AT90S/LS4434 and AT90S/LS8535
111
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 “1” 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
$3E ($5E)
SPH
-
-
-
-
-
-
SP9
SP8
$3D ($5D)
SPL
SP7
SP6
SP5
SP4
SP3
SP2
SP1
SP0
$3C ($5C)
Reserved
$3B ($5B)
GIMSK
INT1
INT0
-
-
-
-
-
-
$3A ($5A)
GIFR
INTF1
INTF0
$39 ($59)
TIMSK
OCIE2
TOIE2
TICIE1
OCIE1A
OCIE1B
TOIE1
-
TOIE0
$38 ($58)
TIFR
OCF2
TOV2
ICF1
OCF1A
OCF1B
TOV1
-
TOV0
$37 ($57)
Reserved
$36 ($56)
Reserved
$35 ($55)
MCUCR
-
SE
SM1
SM0
ISC11
ISC10
ISC01
ISC00
$34 ($54)
MCUSR
-
-
-
-
-
-
EXTRF
PORF
$33 ($53)
TCCR0
-
-
-
-
-
CS02
CS01
CS00
$32 ($52)
TCNT0
Timer/Counter0 (8 Bits)
$31 ($51)
Reserved
$30 ($50)
Reserved
$2F ($4F)
TCCR1A
COM1A1
COM1A0
COM1B1
COM1B0
-
-
PWM11
PWM10
$2E ($4E)
TCCR1B
ICNC1
ICES1
-
-
CTC1
CS12
CS11
CS10
$2D ($4D)
TCNT1H
Timer/Counter1 – Counter Register High Byte
$2C ($4C)
TCNT1L
Timer/Counter1 – Counter Register Low Byte
$2B ($4B)
OCR1AH
Timer/Counter1 – Output Compare Register A High Byte
$2A ($4A)
OCR1AL
Timer/Counter1 – Output Compare Register A Low Byte
$29 ($49)
OCR1BH
Timer/Counter1 – Output Compare Register B High Byte
$28 ($48)
OCR1BL
Timer/Counter1 – Output Compare Register B Low Byte
$27 ($47)
ICR1H
Timer/Counter1 – Input Capture Register High Byte
$26 ($46)
ICR1L
Timer/Counter1 – Input Capture Register Low Byte
$25 ($45)
TCCR2
-
PWM2
COM21
COM20
CTC2
CS22
CS21
CS20
$24 ($44)
TCNT2
Timer/Counter2 (8 Bits)
$23 ($43)
OCR2
Timer/Counter2 Output Compare Register
$22 ($42)
ASSR
-
-
-
-
AS2
TCN2UB
OCR2UB
TCR2UB
$21 ($41)
WDTCR
-
-
-
WDTOE
WDE
WDP2
WDP1
WDP0
$20 ($40)
Reserved
$1F ($3F)
EEARH
EEAR9
$1E ($3E)
EEARL
EEAR7
EEAR6
EEAR5
EEAR4
EEAR3
EEAR2
EEAR1
EEAR0
$1D ($3D)
EEDR
EEPROM Data Register
$1C ($3C)
EECR
-
-
-
-
EERIE
EEMWE
EEWE
EERE
$1B ($3B)
PORTA
PORTA7
PORTA6
PORTA5
PORTA4
PORTA3
PORTA2
PORTA1
PORTA0
$1A ($3A)
DDRA
DDA7
DDA6
DDA5
DDA4
DDA3
DDA2
DDA1
DDA0
$19 ($39)
PINA
PINA7
PINA6
PINA5
PINA4
PINA3
PINA2
PINA1
PINA0
$18 ($38)
PORTB
PORTB7
PORTB6
PORTB5
PORTB4
PORTB3
PORTB2
PORTB1
PORTB0
$17 ($37)
DDRB
DDB7
DDB6
DDB5
DDB4
DDB3
DDB2
DDB1
DDB0
$16 ($36)
PINB
PINB7
PINB6
PINB5
PINB4
PINB3
PINB2
PINB1
PINB0
$15 ($35)
PORTC
PORTC7
PORTC6
PORTC5
PORTC4
PORTC3
PORTC2
PORTC1
PORTC0
$14 ($34)
DDRC
DDC7
DDC6
DDC5
DDC4
DDC3
DDC2
DDC1
DDC0
$13 ($33)
PINC
PINC7
PINC6
PINC5
PINC4
PINC3
PINC2
PINC1
PINC0
$12 ($32)
PORTD
PORTD7
PORTD6
PORTD5
PORTD4
PORTD3
PORTD2
PORTD1
PORTD0
$11 ($31)
DDRD
DDD7
DDD6
DDD5
DDD4
DDD3
DDD2
DDD1
DDD0
$10 ($30)
PIND
PIND7
PIND6
PIND5
PIND4
PIND3
PIND2
PIND1
PIND0
$0F ($2F)
SPDR
SPI Data Register
$0E ($2E)
SPSR
SPIF
WCOL
-
-
-
-
-
-
$0D ($2D)
SPCR
SPIE
SPE
DORD
MSTR
CPOL
CPHA
SPR1
SPR0
$0C ($2C)
UDR
UART I/O Data Register
$0B ($2B)
USR
RXC
TXC
UDRE
FE
OR
-
-
-
$0A ($2A)
UCR
RXCIE
TXCIE
UDRIE
RXEN
TXEN
CHR9
RXB8
TXB8
$09 ($29)
UBRR
UART Baud Rate Register
$08 ($28)
ACSR
ACD
-
ACO
ACI
ACIE
ACIC
ACIS1
ACIS0
$07 ($27)
ADMUX
-
-
-
-
-
MUX2
MUX1
MUX0
$06 ($26)
ADCSR
ADEN
ADSC
ADFR
ADIF
ADIE
ADPS2
ADPS1
ADPS0
$05 ($25)
ADCH
-
-
-
-
-
-
ADC9
ADC8
$04 ($24)
ADCL
ADC7
ADC6
ADC5
ADC4
ADC3
ADC2
ADC1
ADC0
$03 ($20)
Reserved
$02 ($22)
Reserved
$01 ($21)
Reserved
$00 ($20)
Reserved