Low-Power Timer (Lptim); Introduction; Lptim Main Features; Lptim Implementation - ST STM32F423 Reference Manual

RM0430
21

Low-power timer (LPTIM)

21.1

Introduction

The LPTIM is a 16-bit timer that benefits from the ultimate developments in power
consumption reduction. Thanks to its diversity of clock sources, the LPTIM is able to keep
running in all power modes except for Standby mode. Given its capability to run even with
no internal clock source, the LPTIM can be used as a "Pulse Counter" which can be useful
in some applications. Also, the LPTIM capability to wake up the system from low-power
modes, makes it suitable to realize "Timeout functions" with extremely low power
consumption.
The LPTIM introduces a flexible clock scheme that provides the needed functionalities and
performance, while minimizing the power consumption.
21.2

LPTIM main features

•
16 bit upcounter
•
3-bit prescaler with 8 possible dividing factors (1,2,4,8,16,32,64,128)
•
Selectable clock
–
–
•
16 bit ARR autoreload register
• 16 bit compare register
•
Continuous/One-shot mode
• Selectable software/hardware input trigger
•
Programmable Digital Glitch filter
• Configurable output: Pulse, PWM
•
Configurable I/O polarity
• Encoder mode
21.3

LPTIM implementation

Table 115
Encoder mode
1. X = supported.
Internal clock sources: LSE, LSI, HSI or APB clock
External clock source over LPTIM input (working with no LP oscillator running,
used by Pulse Counter application)
describes LPTIM implementation on STM32F413/423 devices.

Table 115. STM32F413/423 LPTIM features

LPTIM modes/features
(1)
RM0430 Rev 8
Low-power timer (LPTIM)
LPTIM1
X
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