ATmega16U4/ATmega32U4
Address
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Page
(0x7C)
(0x7B)
ADMUX
ADCSRB
ADCSRA
ADCH
REFS1
ADHSM
ADEN
REFS0
ACME
ADSC
ADLAR
MUX5
MUX4
-
MUX3
ADTS3
ADIE
MUX2
ADTS2
ADPS2
MUX1
ADTS1
ADPS1
MUX0
ADTS0
ADPS0
(0x7A)
ADATE
ADIF
(0x79)
ADC Data Register High byte
ADC Data Register Low byte
(0x78)
ADCL
(0x77)
Reserved
Reserved
Reserved
Reserved
Reserved
TIMSK4
TIMSK3
Reserved
TIMSK1
TIMSK0
Reserved
Reserved
PCMSK0
EICRB
-
-
-
-
-
-
-
-
(0x76)
-
-
-
-
-
-
-
-
(0x75)
-
-
-
-
-
-
-
-
(0x74)
-
-
-
-
-
-
-
-
(0x73)
-
-
-
-
-
-
-
-
(0x72)
OCIE4D
OCIE4A
OCIE4B
-
-
TOIE4
-
-
TOIE3
-
(0x71)
-
-
ICIE3
-
OCIE3C
OCIE3B
OCIE3A
(0x70)
-
-
-
-
-
-
-
(0x6F)
-
-
ICIE1
-
OCIE1C
OCIE1B
OCIE1A
TOIE1
TOIE0
-
(0x6E)
-
-
-
-
-
OCIE0B
OCIE0A
(0x6D)
-
-
-
-
-
-
-
(0x6C)
-
-
-
PCINT5
ISC61
ISC21
-
-
PCINT4
ISC60
ISC20
-
-
-
-
-
(0x6B)
PCINT7
PCINT6
PCINT3
PCINT2
PCINT1
PCINT0
-
(0x6A)
-
-
-
-
-
(0x69)
EICRA
ISC31
ISC30
ISC11
ISC10
ISC01
ISC00
PCIE0
RCFREQ
(0x68)
PCICR
-
-
-
-
-
-
-
-
-
-
(0x67)
RCCTRL
OSCCAL
PRR1
-
-
(0x66)
RC Oscillator Calibration Register
(0x65)
PRUSB
-
-
PRTIM4
PRTIM3
-
-
PRUSART1
(0x64)
PRR0
PRTWI
-
PRTIM0
-
PRTIM1
PRSPI
-
PRADC
(0x63)
Reserved
Reserved
CLKPR
-
-
-
-
-
-
-
-
(0x62)
-
-
-
-
-
-
-
CLKPS1
WDP1
Z
-
(0x61)
CLKPCE
-
-
-
CLKPS3
CLKPS2
CLKPS0
(0x60)
WDTCSR
SREG
WDIF
WDIE
WDP3
WDCE
WDE
WDP2
WDP0
0x3F (0x5F)
0x3E (0x5E)
0x3D (0x5D)
0x3C (0x5C)
0x3B (0x5B)
0x3A (0x5A)
0x39 (0x59)
0x38 (0x58)
0x37 (0x57)
0x36 (0x56)
0x35 (0x55)
0x34 (0x54)
0x33 (0x53)
0x32 (0x52)
I
T
H
S
V
N
C
SPH
SP15
SP14
SP13
SP12
SP11
SP10
SP9
SP1
-
SP8
SPL
SP7
SP6
SP5
SP4
SP3
SP2
SP0
Reserved
RAMPZ
Reserved
Reserved
Reserved
SPMCSR
Reserved
MCUCR
MCUSR
SMCR
-
-
-
-
-
-
-
-
-
-
-
-
-
RAMPZ1
-
RAMPZ0
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
RWWSRE
-
-
-
SPMIE
RWWSB
SIGRD
BLBSET
-
PGWRT
-
PGERS
-
SPMEN
-
-
-
-
-
JTD
-
PUD
-
-
IVSEL
EXTRF
SM0
PDIV1
OCDR1
IVCE
PORF
SE
-
-
USBRF
-
JTRF
-
WDRF
SM2
PDIV3
OCDR3
BORF
SM1
PDIV2
OCDR2
-
-
PLLFRQ
PINMUX
OCDR7
PLLUSB
OCDR6
PLLTM1
OCDR5
PLLTM0
OCDR4
PDIV0
OCDR0
OCDR/
MONDR
0x31 (0x51)
Monitor Data Register
0x30 (0x50)
0x2F (0x4F)
0x2E (0x4E)
0x2D (0x4D)
0x2C (0x4C)
0x2B (0x4B)
0x2A (0x4A)
0x29 (0x49)
0x28 (0x48)
0x27 (0x47)
0x26 (0x46)
0x25 (0x45)
0x24 (0x44)
0x23 (0x43)
0x22 (0x42)
0x21 (0x41)
0x20 (0x40)
0x1F (0x3F)
0x1E (0x3E)
0x1D (0x3D)
0x1C (0x3C)
ACSR
Reserved
SPDR
ACD
-
ACBG
-
ACO
-
ACI
-
ACIE
-
ACIC
-
ACIS1
-
ACIS0
-
SPI Data Register
-
SPSR
SPIF
SPIE
WCOL
SPE
-
-
-
-
SPI2X
SPR0
SPCR
DORD
MSTR
CPOL
CPHA
SPR1
GPIOR2
GPIOR1
PLLCSR
OCR0B
OCR0A
TCNT0
TCCR0B
TCCR0A
GTCCR
EEARH
EEARL
EEDR
General Purpose I/O Register 2
General Purpose I/O Register 1
-
-
-
PINDIV
-
-
PLLE
PLOCK
Timer/Counter0 Output Compare Register B
Timer/Counter0 Output Compare Register A
Timer/Counter0 (8 Bit)
FOC0A
COM0A1
TSM
FOC0B
-
-
WGM02
CS02
CS01
CS00
COM0A0
COM0B1
COM0B0
-
-
-
-
WGM01
PSRASY
WGM00
-
-
-
-
-
-
PSRSYNC
-
EEPROM Address Register High Byte
EEPROM Address Register Low Byte
EEPROM Data Register
EECR
-
-
EEPM1
EEPM0
EERIE
EEMPE
EEPE
EERE
GPIOR0
EIMSK
EIFR
General Purpose I/O Register 0
-
-
INT6
-
-
-
-
INT3
INT2
INT1
INT0
INTF6
INTF3
INTF2
INTF1
INTF0
11
7766ES–AVR–04/10
ATMEL [ ATMEL ]
