Datasheet

Offset Name Info
0x38 CLK_REF_SELECTED Indicates which SRC is currently selected by the glitchless mux
(one-hot).
0x3c CLK_SYS_CTRL Clock control, can be changed on-the-fly (except for auxsrc)
0x40 CLK_SYS_DIV Clock divisor, can be changed on-the-fly
0x44 CLK_SYS_SELECTED Indicates which SRC is currently selected by the glitchless mux
(one-hot).
0x48 CLK_PERI_CTRL Clock control, can be changed on-the-fly (except for auxsrc)
0x50 CLK_PERI_SELECTED Indicates which SRC is currently selected by the glitchless mux
(one-hot).
0x54 CLK_USB_CTRL Clock control, can be changed on-the-fly (except for auxsrc)
0x58 CLK_USB_DIV Clock divisor, can be changed on-the-fly
0x5c CLK_USB_SELECTED Indicates which SRC is currently selected by the glitchless mux
(one-hot).
0x60 CLK_ADC_CTRL Clock control, can be changed on-the-fly (except for auxsrc)
0x64 CLK_ADC_DIV Clock divisor, can be changed on-the-fly
0x68 CLK_ADC_SELECTED Indicates which SRC is currently selected by the glitchless mux
(one-hot).
0x6c CLK_RTC_CTRL Clock control, can be changed on-the-fly (except for auxsrc)
0x70 CLK_RTC_DIV Clock divisor, can be changed on-the-fly
0x74 CLK_RTC_SELECTED Indicates which SRC is currently selected by the glitchless mux
(one-hot).
0x78 CLK_SYS_RESUS_CTRL
0x7c CLK_SYS_RESUS_STATUS
0x80 FC0_REF_KHZ Reference clock frequency in kHz
0x84 FC0_MIN_KHZ Minimum pass frequency in kHz. This is optional. Set to 0 if you
are not using the pass/fail flags
0x88 FC0_MAX_KHZ Maximum pass frequency in kHz. This is optional. Set to 0x1ffffff
if you are not using the pass/fail flags
0x8c FC0_DELAY Delays the start of frequency counting to allow the mux to settle
Delay is measured in multiples of the reference clock period
0x90 FC0_INTERVAL The test interval is 0.98us * 2**interval, but let’s call it 1us *
2**interval
The default gives a test interval of 250us
0x94 FC0_SRC Clock sent to frequency counter, set to 0 when not required
Writing to this register initiates the frequency count
0x98 FC0_STATUS Frequency counter status
0x9c FC0_RESULT Result of frequency measurement, only valid when
status_done=1
0xa0 WAKE_EN0 enable clock in wake mode
0xa4 WAKE_EN1 enable clock in wake mode
RP2040 Datasheet
2.15. Clocks 219