Start Conversion On External Event; Figure 29. Discontinuous Conversion Mode - Holtek HT32F50231 User Manual

32-Bit Arm ® Cortex ® -M0+ MCU
HT32F50231/HT32F50241
Discontinuous Conversion Mode
CH2 CH4
Subgroup 0
Start of
Conversion
Single sample
End of
Conversion
Subgroup End
of Conversion
Cycle End of
Conversion

Figure 29. Discontinuous Conversion Mode

Start Conversion on External Event

An A/D converter conversion can be initiated by a software trigger, a General-Purpose Timer
Module (GPTM) event, a Motor Control Timer Module (MCTM) event, a PWM Trigger Event,
a Basic Function Timer Module (BFTM) event or an external trigger. Each trigger source can be
enabled by setting the corresponding enable control bit in the ADCTCR register and then selected
by configuring the associated selection bits in the ADCTSR register to start a group channel
conversion.
An A/D converter conversion can be started by setting the software trigger bit, ADSC, in the
ADCTSR register for the group channel when the software trigger enable bit, ADSW, in the
ADCTCR register is set to 1. After the A/D converter starts converting the analog data, the
corresponding enable bit ADSC will be cleared to 0 automatically.
The A/D converter can also be triggered to start a group conversion by a Timer event. The Timer
events include a PWM master trigger output MTO, four PWM channel outputs CH0 ~ CH3, a
GPTM or MCTM master trigger output MTO, four GPTM or MCTM channel outputs CH0 ~ CH3
and a BFTM trigger output. If the corresponding Timer trigger enable bit is set to 1 and the trigger
output or the Timer channel event is selected via the relevant Timer event selection bits, the A/D
converter will start a conversion when a rising edge of the selected trigger event occurs.
In addition to the internal trigger sources, the A/D converter can be triggered to start a conversion
by an external trigger event. The external trigger event is derived from the external lines of the
EXTI unit. If the external trigger enable bit ADEXTI is set to 1 and the corresponding EXTI line is
selected by configuring the ADEXTIS field in the ADCTSR register, the A/D converter will start a
conversion when an EXTI line activity occurs.
Rev. 1.00
(ex: Sequence Length=8, Subgroup Length=3 )
Cycle
CH7 CH5 CH6
Subgroup 1
166 of 486
CH3 CH0 CH1
Subgroup 2
Cycle
CH2 CH4 CH7
Subgroup 0
July 31, 2018