AVR16DU20 CLKCTRL registers

The 14 registers of CLKCTRL (Clock controller), from 0x60, with their reset value and every field. The AVR16DU20 has 408 registers in 39 peripherals, one page each.

CLKCTRL Clock controller

MCLKCTRLAMCLK Control A

Address
0x60
Reset
0x00
Access
read/write
  1. 7CLKOUT
  2. 6–
  3. 5–
  4. 4–
  5. 3–
  6. 2CLKSEL2
  7. 1CLKSEL1
  8. 0CLKSEL0
2 fields
FieldBitsWhat it does
CLKOUT7System clock out
CLKSEL2:0Clock select
  • 0 Internal high-frequency oscillator
  • 1 Internal 32.768 kHz oscillator
  • 2 32.768 kHz crystal oscillator
  • 3 External clock

MCLKCTRLBMCLK Control B

Address
0x61
Reset
0x00
Access
read/write
  1. 7–
  2. 6–
  3. 5–
  4. 4PDIV3
  5. 3PDIV2
  6. 2PDIV1
  7. 1PDIV0
  8. 0PEN
2 fields
FieldBitsWhat it does
PDIV4:1Prescaler division
  • 0 Divide by 2
  • 1 Divide by 4
  • 2 Divide by 8
  • 3 Divide by 16
  • 4 Divide by 32
  • 5 Divide by 64
  • 8 Divide by 6
  • 9 Divide by 10
  • 10 Divide by 12
  • 11 Divide by 24
  • 12 Divide by 48
PEN0Prescaler enable

MCLKCTRLCMCLK Control C

Address
0x62
Reset
0x00
Access
read/write
  1. 7–
  2. 6–
  3. 5–
  4. 4–
  5. 3CFDSRC1
  6. 2CFDSRC0
  7. 1CFDTST
  8. 0CFDEN
3 fields
FieldBitsWhat it does
CFDSRC3:2Clock Failure Detect Source
  • 0 Main Clock
  • 1 XOSCHF
  • 2 XOSC32K
CFDTST1Clock Failure Detect Test
CFDEN0Clock Failure Detect Enable

MCLKINTCTRLMCLK Interrupt Control

Address
0x63
Reset
0x00
Access
read/write
  1. 7INTTYPE
  2. 6–
  3. 5–
  4. 4–
  5. 3–
  6. 2–
  7. 1–
  8. 0CFD
2 fields
FieldBitsWhat it does
INTTYPE7Interrupt type
  • 0 Regular Interrupt
  • 1 NMI
CFD0Clock Failure Detect Interrupt Enable

MCLKINTFLAGSMCLK Interrupt Flags

Address
0x64
Reset
0x00
Access
read/write
  1. 7–
  2. 6–
  3. 5–
  4. 4–
  5. 3–
  6. 2–
  7. 1–
  8. 0CFD
1 field
FieldBitsWhat it does
CFD0Clock Failure Detect Interrupt Flag

MCLKSTATUSMCLK Status

Address
0x65
Reset
0x00
Access
read only
  1. 7–
  2. 6–
  3. 5–
  4. 4EXTS
  5. 3XOSC32KS
  6. 2OSC32KS
  7. 1OSCHFS
  8. 0SOSC
5 fields
FieldBitsWhat it does
EXTS4External Clock status
XOSC32KS332.768 kHz Crystal Oscillator status
OSC32KS232KHz oscillator status
OSCHFS1High frequency oscillator status
SOSC0System Oscillator changing

MCLKTIMEBASETimebase

Address
0x66
Reset
0x00
Access
read/write
  1. 7–
  2. 6–
  3. 5–
  4. 4TIMEBASE4
  5. 3TIMEBASE3
  6. 2TIMEBASE2
  7. 1TIMEBASE1
  8. 0TIMEBASE0
1 field
FieldBitsWhat it does
TIMEBASE4:0Timebase

OSCHFCTRLAOSCHF Control A

Address
0x68
Reset
0x0C
Access
read/write
  1. 7RUNSTDBY
  2. 6ALGSEL
  3. 5FRQSEL3
  4. 4FRQSEL2
  5. 3FRQSEL1
  6. 2FRQSEL0
  7. 1AUTOTUNE1
  8. 0AUTOTUNE0
4 fields
FieldBitsWhat it does
RUNSTDBY7Run standby
ALGSEL6Algorithm Selection
  • 0 Binary Search
  • 1 Incremental Search
FRQSEL5:2Frequency select
  • 0 1 MHz system clock
  • 1 2 MHz system clock
  • 2 3 MHz system clock
  • 3 4 MHz system clock (default)
  • 5 8 MHz system clock
  • 6 12 MHz system clock
  • 7 16 MHz system clock
  • 8 20 MHz system clock
  • 9 24 MHz system clock
AUTOTUNE1:0Autotune
  • 0 Automatic tuning disabled
  • 1 Automatic tuning against XOSC32K enabled
  • 2 Automatic tuning against USB SOF enabled

OSCHFTUNEOSCHF Tune

Address
0x69
Reset
0x00
Access
read/write
  1. 7–
  2. 6TUNE6
  3. 5TUNE5
  4. 4TUNE4
  5. 3TUNE3
  6. 2TUNE2
  7. 1TUNE1
  8. 0TUNE0
1 field
FieldBitsWhat it does
TUNE6:0Tune

OSCHFSTATUSOSCHF Status

Address
0x6A
Reset
0x00
Access
read only
  1. 7–
  2. 6–
  3. 5–
  4. 4–
  5. 3–
  6. 2–
  7. 1ATLOCK
  8. 0ATSYNC
2 fields
FieldBitsWhat it does
ATLOCK1Autotune Synchronized
ATSYNC0Autotune in Lock

OSC32KCTRLAOSC32K Control A

Address
0x78
Reset
0x00
Access
read/write
  1. 7RUNSTDBY
  2. 6–
  3. 5–
  4. 4–
  5. 3–
  6. 2–
  7. 1–
  8. 0–
1 field
FieldBitsWhat it does
RUNSTDBY7Run standby

XOSC32KCTRLAXOSC32K Control A

Address
0x7C
Reset
0x00
Access
read/write
  1. 7RUNSTDBY
  2. 6–
  3. 5CSUT1
  4. 4CSUT0
  5. 3–
  6. 2SEL
  7. 1LPMODE
  8. 0ENABLE
5 fields
FieldBitsWhat it does
RUNSTDBY7Run standby
CSUT5:4Crystal startup time
  • 0 1k cycles
  • 1 16k cycles
  • 2 32k cycles
  • 3 64k cycles
SEL2Select
  • 0 External crystal connected to the XTAL32K1 and XTAL32K2 pins
  • 1 External clock on the XTAL32K1 pin
LPMODE1Low power mode
ENABLE0Enable

XOSCHFCTRLAXOSCHF Control A

Address
0x80
Reset
0x00
Access
read/write
  1. 7RUNSTBY
  2. 6–
  3. 5CSUTHF1
  4. 4CSUTHF0
  5. 3FRQRANGE1
  6. 2FRQRANGE0
  7. 1SELHF
  8. 0ENABLE
5 fields
FieldBitsWhat it does
RUNSTBY7Run Standby
CSUTHF5:4Start-up Time Select
  • 0 256 XOSCHF cycles
  • 1 1K XOSCHF cycles
  • 2 4K XOSCHF cycles
FRQRANGE3:2Frequency Range
  • 0 Max 8 MHz XTAL Frequency
  • 1 Max 16 MHz XTAL Frequency
  • 2 Max 24 MHz XTAL Frequency
  • 3 Max 32 MHz XTAL Frequency
SELHF1External Source Select
  • 0 External Crystal
  • 1 External clock on XTALHF1 pin
ENABLE0Enable

USBPLLSTATUSPLL Status

Address
0x85
Reset
0x00
Access
read only
  1. 7–
  2. 6–
  3. 5–
  4. 4–
  5. 3–
  6. 2–
  7. 1–
  8. 0PLLS
1 field
FieldBitsWhat it does
PLLS0PLL Stable