
Rev. 1.00
177 of 576
January 28, 2022
32-Bit Arm
®
Cortex
®
-M0+ MCU
HT32F54231/HT32F54241/HT32F54243/HT32F54253
10 Nested V
ectored Interrupt Controller (NVIC)
10 Nested V
ectored Interrupt Controller (NVIC)
Functional Descriptions
SysTick Calibration
The SysTick Calibration Value Register (SYST_CALIB) is provided by the NVIC to give a reference
time base of 1ms for the RTOS tick timer or other purposes. The TENMS field in the SYST_CALIB
register has a fixed value of 7500 which is the Counter-Reload value to indicate 1 ms when the
clock source comes from the SysTick reference input clock STCLK with a frequency of 7.5 MHz
(60 MHz divide by 8).
Register Map
The following table shows the NVIC registers and reset values.
Table 26. NVIC Register Map
Register
Offset
Description
Reset Value
NVIC Base Address = 0xE000_E000
SYST_CSR
0x010
SysTick Control and Status Register
0x0000_0000
SYST_RVR
0x014
SysTick Reload Value Register
Unpredictable
SYST_CVR
0x018
SysTick Current Value Register
Unpredictable
SYST_CALIB
0x01C
SysTick Calibration Value Register
0x4000_1D4C
NVIC_ISER
0x100
Interrupt Set Enable Register
0x0000_0000
NVIC_ICER
0x180
Interrupt Clear Enable Register
0x0000_0000
NVIC_ISPR
0x200
Interrupt Set Pending Register
0x0000_0000
NVIC_ICPR
0x280
Interrupt Clear Pending Register
0x0000_0000
NVIC_IPR0
0x400
Interrupt 0 ~ 3 Priority Register
0x0000_0000
NVIC_IPR1
0x404
Interrupt 4 ~ 7 Priority Register
0x0000_0000
NVIC_IPR2
0x408
Interrupt 8 ~ 11 Priority Register
0x0000_0000
NVIC_IPR3
0x40C
Interrupt 12 ~ 15 Priority Register
0x0000_0000
NVIC_IPR4
0x410
Interrupt 16 ~ 19 Priority Register
0x0000_0000
NVIC_IPR5
0x414
Interrupt 20 ~ 23 Priority Register
0x0000_0000
NVIC_IPR6
0x418
Interrupt 24 ~ 27 Priority Register
0x0000_0000
NVIC_IPR7
0x41C
Interrupt 28 ~ 31 Priority Register
0x0000_0000
CPUID
0xD00
CPUID register
0x410C_C601
ICSR
0xD04
Interrupt Control and State Register
0x0000_0000
VTOR
0xD08
Vector Table Offset Register
0x0000_0000
AIRCR
0xD0C
Application Interrupt and Reset Control Register
0xFA05_0000
SCR
0xD10
System Control Register
0x0000_0000
CCR
0xD14
Configuration and Control Register
0x0000_0208
SHPR2
0xD1C
System Handlers Priority Register 2
0x0000_0000
SHPR3
0xD20
System Handlers Priority Register 3
0x0000_0000
Note:
For more detailed descriptions of the above registers, refer to the “Cortex
®
-M0+ Devices Generic
User Guide” document from Arm.