AT32F421
Series Reference Manual
2022.11.11
Page 51
Rev 2.02
ensure that the APB1 clock frequency does not exceed
120 MHz
Bit 7: 4
AHBDIV
0x0
rw
AHB division
The divided SCLK is used as AHB clock.
0xxx: SCLK not divided
1000: SCLK divided by 2 1100: SCLK divided by 64
1001: SCLK divided by 4 1101: SCLK divided by 128
1010: SCLK divided by 8 1110: SCLK divided by 256
1011: SCLK divided by 16 1111: SCLK divided by 512
Bit 3: 2
SCLKSTS
0x0
R0
System clock select status
00: HICK
01: HEXT
10: PLL
11: Reserved. Kept at its default value.
Bit 1: 0
SCLKSEL
0x0
rw
System clock select
00: HICK
01: HEXT
10: PLL
11: Reserved. Kept at its default value.
4.3.3
Clock interrupt register (CRM_CLKINT)
Access: 0 wait state, accessible by words, half-words and bytes.
Bit
Name
Reset value
Type
Description
Bit 31: 24
Reserved
0x00
resd
Kept at its default value.
Bit 23
CFDFC
0x0
wo
Clock failure detection flag clear
Writing 1 by software to clear CFDF.
0: No effect
1: Clear
Bit 22: 21
Reserved
0x0
resd
Kept at its default value.
Bit 20
PLLSTBLFC
0x0
wo
PLL stable flag clear
Writing 1 by software to clear PLLSTBLF.
0: No effect
1: Clear
Bit 19
HEXTSTBLFC
0x0
wo
HEXT stable flag clear
Writing 1 by software to clear HEXTSTBLF.
0: No effect
1: Clear
Bit 18
HICKSTBLFC
0x0
wo
HICK stable flag clear
Writing 1 by software to clear HICKSTBLF.
0: No effect
1: Clear
Bit 17
LEXTSTBLFC
0x0
wo
LEXT stable flag clear
Writing 1 by software to clear LEXTSTBLF.
0: No effect
1: Clear
Bit 16
LICKSTBLFC
0x0
wo
LICK stable flag clear
Writing 1 by software to clear LICKSTBLF.
0: No effect
1: Clear
Bit 15: 13
Reserved
0x0
resd
Kept at its default value.
Bit 12
PLLSTBLIEN
0x0
rw
PLL stable interrupt enable
0: Disabled
1: Enabled
Bit 11
HEXTSTBLIEN
0x0
rw
HEXT stable interrupt enable
0: Disabled
1: Enabled
Bit 10
HICKSTBLIEN
0x0
rw
HICK stable interrupt enable
0: Disabled
1: Enabled
Bit 9
LEXTSTBLIEN
0x0
rw
LEXT stable interrupt enable
0: Disabled
1: Enabled
Bit 8
LICKSTBLIEN
0x0
rw
LICK stable interrupt enable
0: Disabled