AN3342 Datasheet, PDF (9/39 Pages) STMicroelectronics – Getting started with STM8TL5xxx

AN3342
3
Clock management
Clock management
The STM8TL5xxx has no external clock so no precautionary measures are needed.
3.1
Internal clocks
STM8TL5xxx devices have three kinds of internal clock: A high speed internal clock (HSI)
running at 16 MHz, a low speed internal clock (LSI) running at 38 kHz and a high speed
internal clock dedicated to the ProxSense (HSI_PXS) running at 16 MHz. The HSI_PXS
clock runs once the ProxSense is enabled if the LowPower bit is reset. If LowPower bit is set
HSI_PXS clock runs only when an acquisition is being performed.
After reset, the CPU starts at speed of 2 MHz driven by the internal RC (HSI clock signal)
divided by 8.
Doc ID 18461 Rev 3
9/39