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Rev. 1.00
291 of 576
January 28, 2022
32-Bit Arm
®
Cortex
®
-M0+ MCU
HT32F54231/HT32F54241/HT32F54243/HT32F54253
15 Motor Control T
imer (MCTM)
15 Motor Control T
imer (MCTM)
Clock Controller
The following describes the Timer Module clock controller which determines the internal prescaler
counter clock source.
▆
Internal APB clock f
CLKIN
The default internal clock source is the APB clock f
CLKIN
which is used to drive the counter
prescaler when the slave mode is disabled. When the slave mode selection bits SMSEL are set to
0x4, 0x5 or 0x6, the internal APB clock f
CLKIN
is the counter prescaler driving clock source.
▆
STIED
The counter prescaler can count during each rising edge of the STI signal. This mode can be
selected by setting the SMSEL field to 0x7 in the MDCFR register. Here the counter will act
as an event counter. The input event, known as STI here, can be selected by setting the TRSEL
field to an available value except the value of 0x0. When the STI signal is selected as the clock
source, the internal edge detection circuitry will generate a clock pulse during each STI signal
rising edge to drive the counter prescaler. It is important to note that if the TRSEL field is set to
0x0 to select the software UEV1G bit as the trigger source, then when the SMSEL field is set to
0x7, the counter will be updated instead of counting.
PSCR
CRR
CNTR
Reset
CLK
PSC Prescaler
Reset
CLK
Update Event 1
TM_CNT
f
CLKIN
(Internal APB clock)
STIED
(Trigger events)
TRSEL
SMSEL
Start/Stop
Overflow /
Underflow
CK_PSC
CK_CNT
UEV1G bit
Slave Restart
mode trigger
REPR
Repetition
Down Counter
Dec
Figure 78. MCTM Clock Source Selection