Clock Source Status Register - Ckst - Holtek HT32F12345 User Manual

32-Bit Arm ® Cortex ® -M3 MCU
HT32F12345
Clock Source Status Register – CKST
This register specifies clock source status.
Offset: 0x034
Reset value: 0x0100_0003
31
Type/Reset
23
Type/Reset
15
Type/Reset
7
Type/Reset
Bits Field
[27:24] HSIST
[18:16] HSEST
[11:8] PLLST
[2:0] CKSWST
Rev. 1.10
30 29 28
Reserved
22 21 20
Reserved
14 13 12
Reserved
6 5 4
Reserved
Descriptions
Internal High Speed Clock Occupation Status (CK_HSI)
xxx1: HSI is used by System Clock (CK_SYS) (SW = 0x03)
xx1x: HSI is used by PLL
x1xx: HSI is used by Clock Monitor
1xxx: HSI is used by USB PLL
External High Speed Clock Occupation Status (CK_HSE)
xx1: HSE is used by System Clock (CK_SYS) (SW = 0x02)
x1x: HSE is used by PLL
1xx: HSE is used by USB PLL
PLL Clock Occupation Status
xxx1: PLL is used by System Clock (CK_SYS)
xx1x: PLL is used by USART
x1xx : PLL is used by USB
1xxx : PLL is used by CK_REF
Clock Switch Status
00x: CK_PLL clock out as system clock
010: CK_HSE as system clock
011: CK_HSI as system clock
110: CK_LSE as system clock
111: CK_LSI as system clock
The fields are status to indicate which clock source is using as system clock
currently.
108 of 590
27 26
HSIST
RO 0 RO 0 RO
19 18
HSEST
RO 0 RO
11 10
PLLST
RO 0 RO 0 RO
3 2
CKSWST
RO 0 RO
25 24
0 RO 1
17 16
0 RO 0
9 8
0 RO 0
1 0
1 RO 1
November 28, 2018