Hsi Control Register - Hsicr - Holtek HT32F50231 User Manual

32-Bit Arm ® Cortex ® -M0+ MCU
HT32F50231/HT32F50241
HSI Control Register – HSICR
This register is to control the frequency trimming of HSI RC oscillation.
Offset: 0x040
Reset value: 0xXXXX_0000 where X is undefined
31
Reserved
Type/Reset
23
Type/Reset RW X RW
15
Type/Reset
7
FLOCK
Type/Reset RO 0 RW
Bits Field
[28:24] HSICOARSE HSI Clock Coarse Trimming Value
[23:16] HSIFINE
[7] FLOCK
[6:5] REFCLKSEL Reference Clock Selection
[4] TMSEL
[3] ATMSEL
[2] LTRSEL
Rev. 1.00
30 29 28
RO
22 21 20
X RW X RW
14 13 12
6 5 4
REFCLKSEL TMSEL
0 RW 0 RW
Descriptions
These bits are initialized automatically at startup. They are adjusted by factory
trimming and cannot trim by program.
HSI Clock Fine Trimming Value
These bits are initialized automatically at startup. They are also adjusted by factory
trimming. But these bits provide an additional user-programmable trimming value
that is added to the HSICOARSE[4:0] bits to get more accurate or compensate
the variations in voltage and temperature that influence the frequency of the HSI.
It can be programmed by software or automatically adjusted by the Auto Trimming
Controller (ATC) with an external reference clock.
Frequency Lock
0: HSI frequency is not trimmed into target range
1: HSI frequency is trimmed into target range
0x: Select 32.768 kHz external low speed clock source (LSE)
1x: Select external pin (CKIN) 1 kHz pulse
These bits are used to select the reference clock for the HSI Auto Trimming Controller.
Trimming Mode Selection
0: Automatic by Auto Trimming Controller
1: Manual by user program
This bit is used to select the HSI RC oscillator trimming function by ATC hardware
or user programming via the HSIFINE[7:0] bits in the HSI Control Register.
Automatic Trimming Mode Selection
0: Auto Trimming Controller is used binary search to approach the target range
1: Auto Trimming Controller is used linear search to approach the target range
This bit is selected the automatic trimming method by ATC hardware for HSI RC oscillator.
Lock Target Range Selection
0: 0.1 % variation
1: 0.2 % variation
This bit is selected the lock target range of the internal HSI RC oscillator trimming
function for 0.1 % or 0.2 % variation.
93 of 486
27 26
HSICOARSE
X RO X RO X RO
19 18
HSIFINE
X RW X RW X RW
11 10
Reserved
3 2
ATMSEL LTRSEL
0 RW 0 RW 0 RW
25 24
X RO X
17 16
X RW X
9 8
1 0
ATCEN TRIMEN
0 RW 0
July 31, 2018