Datasheet

DocID028798 Rev 3 37/155
STM32L432KB STM32L432KC Functional overview
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The main features of the touch sensing controller are the following:
• Proven and robust surface charge transfer acquisition principle
• Supports up to 3 capacitive sensing channels
• Up to 3 capacitive sensing channels can be acquired in parallel offering a very good
response time
• Spread spectrum feature to improve system robustness in noisy environments
• Full hardware management of the charge transfer acquisition sequence
• Programmable charge transfer frequency
• Programmable sampling capacitor I/O pin
• Programmable channel I/O pin
• Programmable max count value to avoid long acquisition when a channel is faulty
• Dedicated end of acquisition and max count error flags with interrupt capability
• One sampling capacitor for up to 3 capacitive sensing channels to reduce the system
components
• Compatible with proximity, touchkey, linear and rotary touch sensor implementation
• Designed to operate with STMTouch touch sensing firmware library
Note: The number of capacitive sensing channels is dependent on the size of the packages and
subject to I/O availability.
3.20 Random number generator (RNG)
All devices embed an RNG that delivers 32-bit random numbers generated by an integrated
analog circuit.
3.21 Timers and watchdogs
The STM32L432xx includes one advanced control timers, up to five general-purpose timers,
two basic timers, two low-power timers, two watchdog timers and a SysTick timer. The table
below compares the features of the advanced control, general purpose and basic timers.
Table 9. Timer feature comparison
Timer type Timer
Counter
resolution
Counter
type
Prescaler
factor
DMA
request
generation
Capture/
compare
channels
Complementary
outputs
Advanced
control
TIM1 16-bit
Up, down,
Up/down
Any integer
between 1
and 65536
Yes 4 3
General-
purpose
TIM2 32-bit
Up, down,
Up/down
Any integer
between 1
and 65536
Yes 4 No
General-
purpose
TIM15 16-bit Up
Any integer
between 1
and 65536
Yes 2 1
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