58
AT90S/LS2323/2343
1004D–09/01
Note:
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.
AT90S2323/2343 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)
Reserved
$3D ($5D)
SPL
SP7
SP6
SP5
SP4
SP3
SP2
SP1
SP0
$3C ($5C)
Reserved
$3B ($5B)
GIMSK
-
INT0
-
-
-
-
-
-
$3A ($5A)
GIFR
-
INTF0
$39 ($59)
TIMSK
-
-
-
-
-
-
TOIE0
-
$38 ($58)
TIFR
-
-
-
-
-
-
TOV0
-
$37 ($57)
Reserved
$36 ($56)
Reserved
$35 ($55)
MCUCR
-
-
SE
SM
-
-
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)
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
$20 ($40)
Reserved
$1F ($3F)
Reserved
$1E ($3E)
EEAR
-
EEPROM Address Register
$1D ($3D)
EEDR
EEPROM Data Register
$1C ($3C)
EECR
-
-
-
-
-
EEMWE
EEWE
EERE
$1B ($3B)
Reserved
$1A ($3A)
Reserved
$19 ($39)
Reserved
$18 ($38)
PORTB
-
-
-
PORTB4
PORTB3
PORTB2
PORTB1
PORTB0
$17 ($37)
DDRB
-
-
-
DDB4
DDB3
DDB2
DDB1
DDB0
$16 ($36)
PINB
-
-
-
PINB4
PINB3
PINB2
PINB1
PINB0
$15 ($35)
Reserved
…
Reserved
$00 ($20)
Reserved