Datasheet
STM8L151x2, STM8L151x3 Functional overview
Doc ID 018780 Rev 4 21/112
3.10 System configuration controller and routing interface
The system configuration controller provides the capability to remap some alternate
functions on different I/O ports. TIM4 and ADC1 DMA channels can also be remapped.
The highly flexible routing interface controls the routing of internal analog signals to ADC1,
COMP1, COMP2, and the internal reference voltage V
REFINT
. It also provides a set of
registers for efficiently managing the charge transfer acquisition sequence (Section 3.11:
Touchsensing).
3.11 Touchsensing
Low density STM8L15xxx devices provide a simple solution for adding capacitive sensing
functionality to any application. Capacitive sensing technology is able to detect finger
presence near an electrode which is protected from direct touch by a dielectric (example,
glass, plastic). The capacitive variation introduced by a finger (or any conductive object) is
measured using a proven implementation based on a surface charge transfer acquisition
principle. It consists of charging the electrode capacitance and then transferring a part of the
accumulated charges into a sampling capacitor until the voltage across this capacitor has
reached a specific threshold. In Low density STM8L15xxx devices, the acquisition sequence
is managed either by software or by hardware and it involves analog I/O groups, the routing
interface, and timers.Reliable touch sensing solutions can be quickly and easily
implemented using the free STM8 Touch Sensing Library.
3.12 Timers
Low density STM8L15x devices contain two 16-bit general purpose timers (TIM2 and TIM3)
and one 8-bit basic timer (TIM4).
All the timers can be served by DMA1.
Table 2 compares the features of the advanced control, general-purpose and basic timers.
Table 2. Timer feature comparison
Timer
Counter
resolution
Counter
type
Prescaler factor
DMA1
request
generation
Capture/compare
channels
Complementary
outputs
TIM2
16-bit up/down
Any power of 2
from 1 to 128
Ye s
2
None
TIM3
TIM4 8-bit up
Any power of 2
from 1 to 32768
0