Input filtering mechanism of STM32 timer

The STM32's timer input channel has a filter unit located on each input path (the yellow box in the figure below) and the external trigger input path (the blue box in the figure below). Their function is to filter the input. High frequency interference on the signal.

The specific operation principle is as follows:

The CKD[1:0] in TIMx_CR1 allows the user to set the sampling frequency reference for the input signal. There are three options:
1) Sampling frequency reference fDTS = timer input frequency fCK_INT
2) Sampling frequency reference fDTS=timer input frequency fCK_INT/2
3) Sampling frequency reference fDTS=Timer input frequency fCK_INT/4

The input signal is then sampled using the above frequency as a reference, and is considered a valid input level when successively sampled to N active levels.

The actual sampling frequency and sampling times can be selected by the user program as needed; the filtering parameters of the external trigger input channel are set in the ETF[3:0] of the slave mode control register (TIMx_SMCR); the filtering parameters of each input channel are captured/ Compare mode register 1 (TIMx_CCMR1) or capture/compare mode register 2 (TIMx_CCMR2) in IC1F[3:0], IC2F[3:0], IC3F[3:0], and IC4F[3:0].

For example, when fCK_INT=72MHz, select fDTS=fCK_INT/2=36MHz, sampling frequency fSAMPLING=fDTS/2=18MHz and N=6, then the signal with frequency higher than 3MHz will be filtered by this filter, effectively shielding Interference above 3MHz.

For example, combined with the input capture interrupt, the debounce function of the button can be easily implemented without software intervention; this is a hardware-implemented debounce function, which greatly saves the software overhead and the length of the program code.

Each timer can input up to 4 buttons. This method can also be used for keyboard matrix scanning, and because it is implemented by interrupts, the software does not need to perform frequent scanning operations.

Off-line 12V Battery Smart Pulse Restore System, also be called Battery Maintenance System or Battery Restore Solution: mainly used in the whole industry of Electric Vehicle Battery (EV as electric bike, motor and Car ), Car and Truck Start-up battery, Sightseeing car and Golf Cart power batteryWind and Solar energy storage batteryUPS Back up power systemTelecom base site battery , State Grid and Military battery for sudden affair, etc.

12V Battery Pulse Restore  off-line System fully take into account the inconsistent of the physical resonance frequency between lead sulfate crystal and battery plates, select the optimal frequency of pulse waveform and pulse current intensity to "break" and "decompose" the lead sulfate crystals, ensure the best restoration effect of sulfide battery without any damage to the plates. In order to Reduce Internal Resistance and Increase Battery Capacity and Voltage effectively.

The system is composed of 3 parts and a professional standard restore process: 1) 12V Battery Restorer Device(4.5~300Ah); 2) 12V Battery Digital Pusle Charger; 3) 12V Battery Discharge Tester.  Lead-Acid Battery Restoration system and Solution is applicable to all of Lead Acid Battery(AGM, GEL, VRLA, MF, Flooded, Dry, Traction, Deep cycle and Stationary), and widely used in 12V (4.5~300Ah) cell batteries. 

Product features
1.  The smart pulse with fast rising front is resonant with the crystal of lead sulfate to dissolve the large lead sulfate crystal under the action of charging pulse, which can improve the capacity and prolong the service life of the battery.
2.  No need to add any chemical additives, does not change the internal electrolyte composition of the battery, safe and reliable; For water loss batteries only need to add deionized water before restoring. The output pulse voltage and pulse current are strictly limited.
3.  4 independent output, can repair 4PCS 12V/4.5Ah-300Ah cells at the same time without interference.
4.  Each system is equipped with "capacity selection" gear, according to the different capacity of the battery to select the precise gear, can be ensure better protection of battery plate in repair working.
5.  Each system is provided with automatic repair function, automatic repair system will smartly adjust the pulse duty ratio based on the size and conditions of the battery without anyone on duty.
6.  Each system is equipped with "High resistance repair" function, select the high resistance repair, specially for the long term stored batteries, even if the OCV is 0 Volt, but also can be easily activated.

12V Battery Restore System

12V Battery Restore System,12V Battery Pulse Desulfating Restorer,Battery Repair System,12V Cell Maintenance Charger

Shenzhen Daceen Technology Co., Ltd. ,

Posted on