ATmega16U4/ATmega32U4
4. Register Summary
Address
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Page
(0xFF)
(0xFE)
(0xFD)
(0xFC)
(0xFB)
(0xFA)
(0xF9)
(0xF8)
(0xF7)
(0xF6)
(0xF5)
(0xF4)
(0xF3)
(0xF2)
(0xF1)
(0xF0)
(0xEF)
(0xEE)
(0xED)
(0xEC)
(0xEB)
(0xEA)
(0xE9)
(0xE8)
(0xE7)
(0xE6)
(0xE5)
(0xE4)
(0xE3)
(0xE2)
(0xE1)
(0xE0)
(0xDF)
(0xDE)
(0xDD)
(0xDC)
(0xDB)
(0xDA)
(0xD9)
(0xD8)
(0xD7)
(0xD6)
(0xD5)
(0xD4)
(0xD3)
(0xD2)
(0xD1)
(0xD0)
(0xCF)
(0xCE)
(0xCD)
(0xCC)
(0xCB)
(0xCA)
(0xC9)
(0xC8)
(0xC7)
(0xC6)
(0xC5)
(0xC4)
(0xC3)
(0xC2)
(0xC1)
(0xC0)
(0xBF)
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
UEINT
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
EPINT6:0
-
UEBCHX
UEBCLX
UEDATX
UEIENX
UESTA1X
UESTA0X
UECFG1X
UECFG0X
UECONX
UERST
-
-
-
BYCT10:8
BYCT7:0
DAT7:0
RXSTPE
FLERRE
-
NAKINE
-
-
NAKOUTE
RXOUTE
CTRLDIR
STALLEDE
TXINE
-
-
-
-
CURRBK1:0
NBUSYBK1:0
ALLOC
CFGOK
OVERFI
UNDERFI
EPSIZE2:0
-
DTSEQ1:0
EPBK1:0
-
EPTYPE1:0
-
-
-
-
-
-
EPDIR
EPEN
-
-
STALLRQ
STALLRQC
RSTDT
-
EPRST6:0
UENUM
UEINTX
Reserved
UDMFN
-
-
-
-
-
EPNUM2:0
STALLEDI
FIFOCON
NAKINI
RWAL
NAKOUTI
RXSTPI
RXOUTI
TXINI
-
-
-
-
-
-
-
-
-
-
-
-
-
-
FNCERR
-
-
UDFNUMH
UDFNUML
UDADDR
UDIEN
FNUM10:8
FNUM7:0
ADDEN
UADD6:0
EORSTE
EORSTI
-
-
-
UPRSME
UPRSMI
-
EORSME
EORSMI
-
WAKEUPE
WAKEUPI
-
SOFE
SOFI
LSM
MSOFE
MSOFI
SUSPE
SUSPI
UDINT
UDCON
Reserved
Reserved
Reserved
Reserved
Reserved
USBINT
USBSTA
USBCON
UHWCON
Reserved
Reserved
DT4
RSTCPU
RMWKUP
DETACH
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
ID
-
VBUSTI
VBUS
-
USBE
-
-
-
FRZCLK
-
OTGPADE
-
VBUSTE
UVREGE
-
DT4H3
DT4H2
DT4H1
DT4H0
DT4L3
DT4L2
DT4L1
DT4L0
Reserved
OCR4D
Timer/Counter4 - Output Compare Register D
Timer/Counter4 - Output Compare Register C
Timer/Counter4 - Output Compare Register B
Timer/Counter4 - Output Compare Register A
USART1 I/O Data Register
OCR4C
OCR4B
OCR4A
UDR1
UBRR1H
UBRR1L
Reserved
UCSR1C
UCSR1B
UCSR1A
CLKSTA
CLKSEL1
CLKSEL0
TCCR4E
TCCR4D
TCCR4C
TCCR4B
TCCR4A
TC4H
-
-
-
-
USART1 Baud Rate Register High Byte
USART1 Baud Rate Register Low Byte
-
-
-
-
-
USBS1
TXEN1
DOR1
-
-
-
-
UMSEL11
RXCIE1
RXC1
UMSEL10
TXCIE1
TXC1
UPM11
UDRIE1
UDRE1
-
UPM10
RXEN1
FE1
UCSZ11
UCSZ12
PE1
UCSZ10
RXB81
U2X1
UCPOL1
TXB81
MPCM1
EXTON
EXCKSEL0
CLKS
-
-
-
-
RCON
EXCKSEL1
-
RCCKSEL3
RCSUT1
TLOCK4
FPIE4
RCCKSEL2
RCSUT0
ENHC4
FPEN4
COM4A0S
PSR4
RCCKSEL1
EXSUT1
OC4OE5
FPNC4
COM4B1S
DTPS41
COM4B1
-
RCCKSEL0
EXSUT0
OC4OE4
FPES4
COM4B0S
DTPS40
COM4B0
-
EXCKSEL3
RCE
EXCKSEL2
EXTE
OC4OE3
FPAC4
COM4D1S
CS43
OC4OE2
FPF4
OC4OE1
WGM41
FOC4D
CS41
OC4OE0
WGM40
PWM4D
CS40
COM4A1S
PWM4X
COM4A1
-
COM4D0S
CS42
COM4A0
-
FOC4A
-
FOC4B
PWM4A
PWM4B
Timer/Counter4 High Byte
9
7766ES–AVR–04/10
ATMEL [ ATMEL ]
